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Sample records for water deficit tree

  1. Effect of water deficit on Argan tree seedlings (Argania spinosa L ...

    African Journals Online (AJOL)

    USER

    2015-03-17

    Mar 17, 2015 ... The Argan tree, Argania spinosa L., Skeels, is an endemic species in North-West Africa perfectly adapted to aridity and drought. It is in this context that we studied the physiological impact of water deficit on the Argan tree seedlings for eight weeks at a field capacity of 30%. The obtained results reveal.

  2. CERATOCYSTIS WILT IN ‘UBÁ’ AND ‘DURA’ MANGO TREES UNDER WATER DEFICIT

    OpenAIRE

    SILVA, SAULO DAVID REZENDE DA; Siqueira,Dalmo Lopes de; SALOMÃO, LUIS CARLOS CHAMHUM; Cecon, Paulo Roberto; Alfenas,Acelino Couto

    2017-01-01

    ABSTRACT The occurrence of water stress in mango trees grown in orchards located in semi-arid climates in Brazil is frequent. Water stress caused to plants may predispose them to the incidence of fungal diseases. The aim of this study was to evaluate the effect of water deficit on the incidence and severity of Ceratocystis wilt in mango trees considered resistant. Seedlings of ‘Ubá’ and ‘Dura’ were kept in pots and submitted to different water stress levels and inoculated with Ceratocystis f...

  3. Effect of water deficit on Argan tree seedlings ( Argania spinosa L ...

    African Journals Online (AJOL)

    Effect of water deficit on Argan tree seedlings ( Argania spinosa L. Skeels): Morphological and physiological aspect. ... Besides, the content of chlorophyll pigments has relatively decreased from the second week, a slight yellowing and leaf drop was observed. The seedlings have accumulated proteins in a very significant ...

  4. Temperate tree species show identical response in tree water deficit but different sensitivities in sap flow to summer soil drying.

    Science.gov (United States)

    Brinkmann, Nadine; Eugster, Werner; Zweifel, Roman; Buchmann, Nina; Kahmen, Ansgar

    2016-12-01

    Temperate forests are expected to be particularly vulnerable to drought and soil drying because they are not adapted to such conditions and perform best in mesic environments. Here we ask (i) how sensitively four common temperate tree species (Fagus sylvatica, Picea abies, Acer pseudoplatanus and Fraxinus excelsior) respond in their water relations to summer soil drying and seek to determine (ii) if species-specific responses to summer soil drying are related to the onset of declining water status across the four species. Throughout 2012 and 2013 we determined tree water deficit (TWD) as a proxy for tree water status from recorded stem radius changes and monitored sap flow rates with sensors on 16 mature trees studied in the field at Lägeren, Switzerland. All tree species responded equally in their relative maximum TWD to the onset of declining soil moisture. This implies that the water supply of all tree species was affected by declining soil moisture and that none of the four species was able to fully maintain its water status, e.g., by access to alternative water sources in the soil. In contrast we found strong and highly species-specific responses of sap flow to declining soil moisture with the strongest decline in P. abies (92%), followed by F. sylvatica (53%) and A. pseudoplatanus (48%). F. excelsior did not significantly reduce sap flow. We hypothesize the species-specific responses in sap flow to declining soil moisture that occur despite a simultaneous increase in relative TWD in all species reflect how fast these species approach critical levels of their water status, which is most likely influenced by species-specific traits determining the hydraulic properties of the species tree. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Diurnal variations in water relations of deficit irrigated lemon trees during fruit growth period

    Directory of Open Access Journals (Sweden)

    Y. García-Orellana

    2013-01-01

    Full Text Available Field-grown lemon trees (Citrus limon (L. Burm. fil. cv. Fino were subjected to different drip irrigation treatments: a control treatment, irrigated daily above crop water requirements in order to obtain non-limiting soil water conditions and two deficit irrigation treatments, reducing the water applied according to the maximum daily trunk shrinkage (MDS signal intensity (actual MDS/control treatment MDS threshold values of 1.25 (T1 treatment and 1.35 (T2 treatment, which induced two different drought stress levels. Daily variations in leaf (Yleaf and stem (Ystem water potentials, leaf conductance, net photosynthesis, sap flow (SF and trunk diameter fluctuations were studied on four occasions during the lemon fruit growth period. Ystem and Yleaf revealed a diurnal pattern in response to changes in evaporative demand of the atmosphere. Both water potentials decreased in response to water deficits, which were more pronounced in the T2 treatment. Ystem was seen to be a better plant water status indicator than Yleaf. The difference between the two values of Y (Ystem - Yleaf  = DY was closely correlated with sap flow, making it a suitable measure of leaf transpiration. Using the slope of this relationship, the canopy hydraulic conductance (KC was estimated. When other continuously recorded plant-based indicators are not accessible, the concurrent measurement of leaf and stem water potentials at midday, which are relatively inexpensive to measure and user-friendly, act as sufficiently good indicators of the plant water status in field grown Fino lemon trees.

  6. CERATOCYSTIS WILT IN ‘UBÁ’ AND ‘DURA’ MANGO TREES UNDER WATER DEFICIT

    Directory of Open Access Journals (Sweden)

    SAULO DAVID REZENDE DA SILVA

    2017-10-01

    Full Text Available ABSTRACT The occurrence of water stress in mango trees grown in orchards located in semi-arid climates in Brazil is frequent. Water stress caused to plants may predispose them to the incidence of fungal diseases. The aim of this study was to evaluate the effect of water deficit on the incidence and severity of Ceratocystis wilt in mango trees considered resistant. Seedlings of ‘Ubá’ and ‘Dura’ were kept in pots and submitted to different water stress levels and inoculated with Ceratocystis fimbriata isolate (CEBS15. Mortality was low in ‘Ubá’ plants and high in ‘Dura’ plants. ‘Ubá’ plants showed lower severity and lesion length. In ‘Ubá’ plants, water deficit influenced the increase in lesion length. ‘Dura’ plants showed greater severity and lesion length, which were not affected by increasing water stress. It was concluded that ‘Ubá’ variety is resistant to fungus Ceratocystis fimbriata, even in severe drought conditions, while ‘Dura’ variety was not resistant to CEBS15 isolate, even under optimum irrigation conditions.

  7. Assessment of the effect of water deficit on sap flow of longkong trees by using heat-pulse method

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    Sayan Sdoodee

    2002-04-01

    Full Text Available The effect of water deficit on sap flow of longkong trees was studied by using heat-pulse method. An experiment was carried out in a glasshouse over 30-day period. There were 3 treatments: 1 daily watering or control, 2 5-day interval watering or moderate water deficit (MWD and 3 10-day interval watering or high water deficit (HWD with 4 replications. Twelve longkong trees (3-year old were used. Each tree was grown in a 30L polybag filled with soil mixture. It was found that leaf water potential, stomatal conductance and Fv/Fm (at 10 day interval in the MWD and HWD continuously decreased through the experimental period, and they were significantly different from those of the control at the end of the experimental period. Sap flow in the MWD and HWD treatments were consistently low around day 16 and day 13 after starting the experiment. Concomitantly, stomatal conductance of HWD rapidly decreased from day 10, and it was significantly different from those in MWD and control treatments. This implies that water deficit caused stomatal closure leading to the reduction of transpiration. Hence, it appears that water deficit causes the decrease of sap flow in longkong tree, and this incidence depends on the severity of water deficit.

  8. Diurnal variations in water relations of deficit irrigated lemon trees during fruit growth period

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Orellana, Y.; Ortuno, M. F.; Conejero, W.; Ruiz-Sanchez, M. C.

    2013-05-01

    Field-grown lemon trees (Citrus limon (L.) Burm. fil. cv. Fino) were subjected to different drip irrigation treatments: a control treatment, irrigated daily above crop water requirements in order to obtain non-limiting soil water conditions and two deficit irrigation treatments, reducing the water applied according to the maximum daily trunk shrinkage (MDS) signal intensity (actual MDS/control treatment MDS) threshold values of 1.25 (T1 treatment) and 1.35 (T2 treatment), which induced two different drought stress levels. Daily variations in leaf (Y{sub l}eaf) and stem (Y{sub s}tem) water potentials, leaf conductance, net photosynthesis, sap flow (SF) and trunk diameter fluctuations were studied on four occasions during the lemon fruit growth period. Ystem and Y{sub l}eaf revealed a diurnal pattern in response to changes in evaporative demand of the atmosphere. Both water potentials decreased in response to water deficits, which were more pronounced in the T2 treatment. Y{sub s}tem was seen to be a better plant water status indicator than Y{sub l}eaf. The difference between the two values of Y (Y{sub s}tem - Y{sub l}eaf {Delta}{Psi}) was closely correlated with sap flow, making it a suitable measure of leaf transpiration. Using the slope of this relationship, the canopy hydraulic conductance (KC) was estimated. When other continuously recorded plant-based indicators are not accessible, the concurrent measurement of leaf and stem water potentials at midday, which are relatively inexpensive to measure and user-friendly, act as sufficiently good indicators of the plant water status in field grown Fino lemon trees. (Author) 40 refs.

  9. Water deficits in timberline trees in the Snowy Mountains of South-Eastern Australia.

    Science.gov (United States)

    Slatyer, R O

    1976-12-01

    Leaf water potential (Ψ), leaf diffusion resistance (r 1 ) and net photosynthesis of leaves of Eucalyptus pauciflora Sieb at timberline (2,040 m) were measured in winter and spring in the Snowy Mountains area of southeastern Australia. Four treatments were established in a 2×2 factorial design involving exposure to direct sunlight, screening to reduce solar radiation by approximately 50%, exposure to direct radiant cooling at night, and screening to reduce radiant cooling. A less comprehensive set of measurements was also made in summer.No significant water deficits developed in any of the treatments, water potentials remaining above Ψ=-14 bars in winter, and above Ψ=-10 bars in spring, well above the levels needed to cause tissue damage in this species. These results contrast with the extreme desiccation reported in trees at timberline in other regions and suggest that winter dehydration is not an important factor in limiting tree distribution in the Snowy Mountains.Tissue damage was observed in all treatments and was most pronounced in those exposed to natural radiation frosts, in which shoot die-back occurred. Although factors other than frost incidence may have been influenced by the treatments, the results suggest that low temperatures, possibly associated with periods of clear weather and cold nights in the spring, when the tissue was no longer winter-hardy, may have been the main factors responsible.

  10. Climatic water deficit, tree species ranges, and climate change in Yosemite National Park

    Science.gov (United States)

    James A. Lutz; Jan W. van Wagtendonk; Jerry F. Franklin

    2010-01-01

    Modelled changes in climate water deficit between past, present and future climate scenarios suggest that recent past changes in forest structure and composition may accelerate in the future, with species responding individualistically to further declines in water availability. Declining water availability may disproportionately affect Pinus monticola...

  11. Differences in proleptic and epicormic shoot structures in relation to water deficit and growth rate in almond trees (Prunus dulcis).

    Science.gov (United States)

    Negrón, Claudia; Contador, Loreto; Lampinen, Bruce D; Metcalf, Samuel G; Guédon, Yann; Costes, Evelyne; DeJong, Theodore M

    2014-02-01

    Shoot characteristics differ depending on the meristem tissue that they originate from and environmental conditions during their development. This study focused on the effects of plant water status on axillary meristem fate and flowering patterns along proleptic and epicormic shoots, as well as on shoot growth rates on 'Nonpareil' almond trees (Prunus dulcis). The aims were (1) to characterize the structural differences between proleptic and epicormic shoots, (2) to determine whether water deficits modify shoot structures differently depending on shoot type, and (3) to determine whether shoot structures are related to shoot growth rates. A hidden semi-Markov model of the axillary meristem fate and number of flower buds per node was built for two shoot types growing on trees exposed to three plant water status treatments. The models segmented observed shoots into successive homogeneous zones, which were compared between treatments. Shoot growth rates were calculated from shoot extension measurements made during the growing season. Proleptic shoots had seven successive homogeneous zones while epicormic shoots had five zones. Shoot structures were associated with changes in growth rate over the season. Water deficit (1) affected the occurrence and lengths of the first zones of proleptic shoots, but only the occurrence of the third zone was reduced in epicormic shoots; (2) had a minor effect on zone flowering patterns and did not modify shoot or zone composition of axillary meristem fates; and (3) reduced growth rates, although patterns over the season were similar among treatments. Two meristem types, with different latency durations, produced shoots with different growth rates and distinct structures. Differences between shoot type structure responses to water deficit appeared to reflect their ontogenetic characteristics and/or resource availability for their development. Tree water deficit appeared to stimulate a more rapid progression through ontogenetic states.

  12. Rapid and long-term effects of water deficit on gas exchange and hydraulic conductance of silver birch trees grown under varying atmospheric humidity.

    Science.gov (United States)

    Sellin, Arne; Niglas, Aigar; Õunapuu-Pikas, Eele; Kupper, Priit

    2014-03-24

    Effects of water deficit on plant water status, gas exchange and hydraulic conductance were investigated in Betula pendula under artificially manipulated air humidity in Eastern Estonia. The study was aimed to broaden an understanding of the ability of trees to acclimate with the increasing atmospheric humidity predicted for northern Europe. Rapidly-induced water deficit was imposed by dehydrating cut branches in open-air conditions; long-term water deficit was generated by seasonal drought. The rapid water deficit quantified by leaf (ΨL) and branch water potentials (ΨB) had a significant (P gas exchange parameters, while inclusion of ΨB in models resulted in a considerably better fit than those including ΨL, which supports the idea that stomatal openness is regulated to prevent stem rather than leaf xylem dysfunction. Under moderate water deficit (ΨL≥-1.55 MPa), leaf conductance to water vapour (gL), transpiration rate and leaf hydraulic conductance (KL) were higher (P < 0.05) and leaf temperature lower in trees grown in elevated air humidity (H treatment) than in control trees (C treatment). Under severe water deficit (ΨL<-1.55 MPa), the treatments showed no difference. The humidification manipulation influenced most of the studied characteristics, while the effect was to a great extent realized through changes in soil water availability, i.e. due to higher soil water potential in H treatment. Two functional characteristics (gL, KL) exhibited higher (P < 0.05) sensitivity to water deficit in trees grown under increased air humidity. The experiment supported the hypothesis that physiological traits in trees acclimated to higher air humidity exhibit higher sensitivity to rapid water deficit with respect to two characteristics - leaf conductance to water vapour and leaf hydraulic conductance. Disproportionate changes in sensitivity of stomatal versus leaf hydraulic conductance to water deficit will impose greater risk of desiccation-induced hydraulic

  13. Nutrients, Trace Elements and Water Deficit in Greek Soils Cultivated with Olive Trees

    Directory of Open Access Journals (Sweden)

    Theodore Karyotis

    2014-11-01

    Full Text Available The studied soils consist of alluvial and/or colluvial deposits  located in the Prefecture of Messinia, Western Peloponnese (Greece. A total number of 263 surface soil layers were selected and analysed for the main properties. Minimum and maximum values and  the distribution of soil properties varied greatly and can be attributed mainly to various fertilization practices adopted by  farmers, inputs of nutrients by irrigation water and differences due to inherent soil conditions. Lower variability was recorded for the parameters pH, Cation Exchange Capacity (CEC, total soil nitrogen (N and soil organic matter (SOM, while coefficients of variation for properties that can be affected easily by human activities such as available phosphorus and micronutrients, are much higher. Minor content for trace elements was observed in the following order:Zinc (Zn>Manganese (Mn>Boron (B>Iron (Fe. During the dry period, irrigation of olive trees is recommended and the appropriate irrigation demands were defined, taking into account rainfall and  water requirements.

  14. Approximate Entropy as a measure of complexity in sap flow temporal dynamics of two tropical tree species under water deficit

    Directory of Open Access Journals (Sweden)

    Gustavo M. Souza

    2004-09-01

    Full Text Available Approximate Entropy (ApEn, a model-independent statistics to quantify serial irregularities, was used to evaluate changes in sap flow temporal dynamics of two tropical species of trees subjected to water deficit. Water deficit induced a decrease in sap flow of G. ulmifolia, whereas C. legalis held stable their sap flow levels. Slight increases in time series complexity were observed in both species under drought condition. This study showed that ApEn could be used as a helpful tool to assess slight changes in temporal dynamics of physiological data, and to uncover some patterns of plant physiological responses to environmental stimuli.Entropia Aproximada (ApEn, um modelo estatístico independente para quantificar irregularidade em séries temporais, foi utilizada para avaliar alterações na dinâmica temporal do fluxo de seiva em duas espécies arbóreas tropicais submetidas à deficiência hídrica. A deficiência hídrica induziu uma grande redução no fluxo de seiva em G. ulmifolia, enquanto que na espécie C. legalis manteve-se estável. A complexidade das séries temporais foi levemente aumentada sob deficiência hídrica. O estudo mostrou que ApEn pode ser usada como um método para detectar pequenas alterações na dinâmica temporal de dados fisiológicos, e revelar alguns padrões de respostas fisiológicas a estímulos ambientais.

  15. Simulating nectarine tree transpiration and dynamic water storage from responses of leaf conductance to light and sap flow to stem water potential and vapor pressure deficit.

    Science.gov (United States)

    Paudel, Indira; Naor, Amos; Gal, Yoni; Cohen, Shabtai

    2015-04-01

    For isohydric trees mid-day water uptake is stable and depends on soil water status, reflected in pre-dawn leaf water potential (Ψpd) and mid-day stem water potential (Ψmd), tree hydraulic conductance and a more-or-less constant leaf water potential (Ψl) for much of the day, maintained by the stomata. Stabilization of Ψl can be represented by a linear relationship between canopy resistance (Rc) and vapor pressure deficit (D), and the slope (BD) is proportional to the steady-state water uptake. By analyzing sap flow (SF), meteorological and Ψmd measurements during a series of wetting and drying (D/W) cycles in a nectarine orchard, we found that for the range of Ψmd relevant for irrigated orchards the slope of the relationship of Rc to D, BD is a linear function of Ψmd. Rc was simulated using the above relationships, and its changes in the morning and evening were simulated using a rectangular hyperbolic relationship between leaf conductance and photosynthetic irradiance, fitted to leaf-level measurements. The latter was integrated with one-leaf, two-leaf and integrative radiation models, and the latter gave the best results. Simulated Rc was used in the Penman-Monteith equation to simulate tree transpiration, which was validated by comparing with SF from a separate data set. The model gave accurate estimates of diurnal and daily total tree transpiration for the range of Ψmds used in regular and deficit irrigation. Diurnal changes in tree water content were determined from the difference between simulated transpiration and measured SF. Changes in water content caused a time lag of 90-105 min between transpiration and SF for Ψmd between -0.8 and -1.55 MPa, and water depletion reached 3 l h(-1) before noon. Estimated mean diurnal changes in water content were 5.5 l day(-1) tree(-1) at Ψmd of -0.9 MPa and increased to 12.5 l day(-1) tree(-1) at -1.45 MPa, equivalent to 6.5 and 16.5% of daily tree water use, respectively. Sixteen percent

  16. When do Acacia mellifera trees use water? Responses of sap velocity to soil water availability, vapour pressure deficit and global radiation.

    Science.gov (United States)

    de Blécourt, Marleen; Thomsen, Simon; Gröngröft, Alexander; Eschenbach, Annette

    2017-04-01

    Acacia mellifera (multi-stem deciduous tree) is one of the dominant woody species responsible for bush encroachment in southern African savannahs. However, very little is known on water use, transpiration or xylem sap flow of A. mellifera. We analyzed the responses of sap velocity in A. mellifera to soil moisture, vapour pressure deficit and global radiation. This knowledge is necessary to improve hydrological modelling and will as such contribute to our understanding of the impacts of bush encroachment in (semi) arid savannahs on the soil water balance. We monitored sap velocities at two sites that differed in tree density in a semi-arid thornbush savannah in central Namibia (mean annual precipitation = 346 mm). Sap velocities were derived using the Heat Ratio Method. Measurements were done in four periods of 3-4 months between November 2014 and September 2016. The measurement periods covered the transitions between the dry and rainy season and vice versa, and the dry season. In two of these periods we did measurements at all stems of three trees per site (a total of 17-19 stems), while in the other two periods sap velocities were measured on one stem per tree for six to eight trees per site. The study was done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management) granted by the German Federal Ministry of Education and Research (BMBF). Preliminary results indicate that the day-to-day fluctuations in cumulative daily sap velocity showed a three-phase interaction with soil water tension (minimum soil water tension of four sensors to 1-m depth). Phase I: At soil water tension water tension had little influence on sap velocities, and fluctuations in sapflow seemed to be related to VPD and global radiation. Phase II: At soil water tensions between pF 2.5 and pF 3.2, sap velocities were negatively related to soil water tension. Phase III: At soil water tensions > pF 3.2 no sap flow could be detected.

  17. Multispectral airborne imagery in the field reveals genetic determinisms of morphological and transpiration traits of an apple tree hybrid population in response to water deficit.

    Science.gov (United States)

    Virlet, Nicolas; Costes, Evelyne; Martinez, Sébastien; Kelner, Jean-Jacques; Regnard, Jean-Luc

    2015-09-01

    Genetic studies of response to water deficit in adult trees are limited by low throughput of the usual phenotyping methods in the field. Here, we aimed at overcoming this bottleneck, applying a new methodology using airborne multispectral imagery and in planta measurements to compare a high number of individuals.An apple tree population, grafted on the same rootstock, was submitted to contrasting summer water regimes over two years. Aerial images acquired in visible, near- and thermal-infrared at three dates each year allowed calculation of vegetation and water stress indices. Tree vigour and fruit production were also assessed. Linear mixed models were built accounting for date and year effects on several variables and including the differential response of genotypes between control and drought conditions.Broad-sense heritability of most variables was high and 18 quantitative trait loci (QTLs) independent of the dates were detected on nine linkage groups of the consensus apple genetic map. For vegetation and stress indices, QTLs were related to the means, the intra-crown heterogeneity, and differences induced by water regimes. Most QTLs explained 15-20% of variance.Airborne multispectral imaging proved relevant to acquire simultaneous information on a whole tree population and to decipher genetic determinisms involved in response to water deficit. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. INFRARED CANOPY TEMPERATURE OF PEACH TREES UNDER DEFICIT IRRIGATION

    Science.gov (United States)

    An early-season peach, “Crimson Lady” (Prunus persica (L.) Batsch), is generally harvested in late May to early June in central California. To reduce water use, regulated deficit irrigation may be applied to these trees for the remaining and also most water demanding season (mid June to November). ...

  19. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

    Science.gov (United States)

    Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew; Kueppers, Lara M.; Moyes, Andrew B.

    2018-01-01

    1.Predictions of upslope range shifts for tree species with warming are based on assumptions of moisture stress at lower elevation limits and low temperature stress at high elevation limits. However, recent studies have shown that warming can reduce tree seedling establishment across the entire gradient from subalpine forest to alpine via moisture limitation. Warming effects also vary with species, potentially resulting in community shifts in high elevation forests. 2.We examined the growth and physiology underlying effects of warming on seedling demographic patterns. We evaluated dry mass (DM), root length, allocation above- and belowground, and relative growth rate (RGR) of whole seedlings, and their ability to avoid or endure water stress via water-use efficiency and resisting turgor loss, for Pinus flexilis, Picea engelmannii and Pinus contorta seeded below, at, and above treeline in experimentally warmed, watered, and control plots in the Rocky Mountains, USA. We expected that growth and allocation responses to warming would relate to moisture status and that variation in drought tolerance traits would explain species differences in survival rates. 3.Across treatments and elevations, seedlings of all species had weak turgor-loss resistance, and growth was marginal with negative RGR in the first growth phase (-0.01 to -0.04 g/g/d). Growth was correlated with soil moisture, particularly in the relatively small-seeded P. contorta and P. engelmannii. P. flexilis, known to have the highest survivorship, attained the greatest DM and longest root but was also the slowest growing and most water-use-efficient. This was likely due to its greater reliance on seed reserves. Seedlings developed 15% less total DM, 25% less root DM, and 11% shorter roots in heated compared to unheated plots. Higher temperatures slightly increased DM, root length and RGR where soils were wettest, but more strongly decreased these variables under drier conditions. 4.Synthesis: The surprising

  20. Morphological, physiological and biochemical responses to soil water deficit in seedlings of three populations of wild pear tree (Pyrus boisseriana

    Directory of Open Access Journals (Sweden)

    Zarafshar, M.

    2014-01-01

    Full Text Available Water shortage limits the production of fruit orchards, such as pear, in arid and semi-arid regions. The identification of wild pear germplasm for potential use as rootstock would be valuable for pear cultivation in semi-arid regions. The relative drought tolerance of wild pear germplasm (Pyrus boisseriana from three different populations distributed along an elevational gradient ('semi-arid 1,000', 'semi-wet 1,350' and 'semi-wet 1,600' populations was evaluated in a greenhouse trial. Established container-grown seedlings were exposed to 18 days of simulated drought, or not, followed by a seven day recovery period. Biomass allocation and accumulation, physiological (stomatal conductance, photosynthesis, transpiration, xylem water potential and biochemical parameters (leaf pigments, free proline, malondialdehyde and hydrogen peroxide production were evaluated. Although all populations were able to recover from water shortage, thereby proving to be relatively drought tolerant, some differences between populations were detected for gas exchange parameters, biomass accumulation and proline concentration in favor of the 'semi-arid 1,000' elevation population, which was more drought tolerant. This population showed the most rapid and complete recovery of physiological activity (stomatal conductance and carbon fixation. In addition, all populations showed an increase in carotenoid content in the leaves. Overall, we showed that plants from the 'semi-arid 1,000' elevation had greater tolerance to drought than those from the higher elevations (semi-wet populations. It therefore appears that plants from the 'semi-arid 1,000' elevation represent a promising source of material to be tested as rootstock for commercial scions of pear in field conditions in areas prone to suffer from water deficit.

  1. Infrared thermometry for deficit irrigation of peach trees

    Science.gov (United States)

    Water shortage has been a major concern for crop production in the western states of the USA and other arid regions in the world. Deficit irrigation can be used in some cropping systems as a potential water saving strategy to alleviate water shortage, however, the margin of error in irrigation manag...

  2. Response of early-peach [Prunus persica (L.)] trees to deficit irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Abrisqueta, I.; Tapia, L. M.; Conejero, W.; Sanchez-Toribio, M. I.; Abrisqueta, J. M.; Vera, J.; Ruiz-Sanchez, C.

    2010-07-01

    The effect of different irrigation strategies in water relations, vegetative growth and yield of early maturing peach trees, growing in Murcia, (Spain) was studied during two years. Treatments consisted on: a control T1, full irrigated (150% of ETc); T2, continuous deficit irrigation at 50% of ETc; T3, regulated deficit irrigation (RDI), irrigated at 100% of ETc only during stage III of fruit growth and 25% the rest of the growing season; and T4, with automatic control of irrigation based on capacitance FDR-type probe data, varying threshold values. The results indicated that irrigation deficits in T2 and T3 treatments induced the lowest soil water content and stem water potential(?stem) values during the post harvest period (e.g {psi}{sub s}tem up to -1.8 MPa in T3 during summer 2008); thus, a reduction in trunk growth and pruning weight, respect to control treatment values, was noted in both years. Also, peach yield was significantly reduced in both deficit irrigated treatments. The greatest irrigation water saving in T3 treatment (=60%) caused the higher water use efficiency values in this treatment. For these reasons, water deficit during the post harvest periods (extended in the early maturing varieties) must be limited if fruit yield is not to be reduced. Irrigation scheduling based on capacitance probes have become a useful tool in the control of soil water content. When threshold values were precisely defined, the slight water deficits limited only vegetative growth while maintaining similar peach yield to that of well irrigated trees. (Author) 31 refs.

  3. Trees, forests and water

    NARCIS (Netherlands)

    Ellison, David; Morris, Cindy E.; Locatelli, Bruno; Sheil, Douglas; Cohen, Jane; Murdiyarso, Daniel; Gutierrez, Victoria; Noordwijk, van Meine; Creed, Irena F.; Pokorny, Jan; Gaveau, David; Spracklen, Dominick V.; Tobella, Aida Bargués; Ilstedt, Ulrik; Teuling, Adriaan J.; Gebrehiwot, Solomon Gebreyohannis; Sands, David C.; Muys, Bart; Verbist, Bruno; Springgay, Elaine; Sugandi, Yulia; Sullivan, Caroline A.

    2017-01-01

    Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity's ability to protect our planet's climate and life-sustaining functions. The

  4. Water use of tree lines: importance of leaf area and micrometeorology in sub-humid Kenya

    NARCIS (Netherlands)

    Radersma, S.; Ong, C.K.; Coe, R.

    2006-01-01

    In this research the relative importance of leaf area and microclimatic factors in determining water use of tree lines was examined in sub-humid Western Kenya. Measurements of tree water-use by a heat-balance technique, leaf area, bulk air saturation deficit, daily radiation, and soil water content

  5. [Effects of tree height on whole-tree water use of Acacia mangium].

    Science.gov (United States)

    Liu, Xiao-jing; Zhao, Ping; Wang, Quan; Cai, Xi-an; Zeng, Xiao-ping

    2009-01-01

    By using Granier's thermal dissipation probe, the sap flow of 14 sample trees in a 22-year old Acacia mangium forest in hilly land of South China was continuously measured in 2004. Environmental factors including the photosynthetically active radiation, air temperature, and air humidity above canopy and the water content in 0-30 cm soil layer were monitored simultaneously. Combining with the tree morphological features and sap flux density, the whole-tree transpiration, canopy stomatal conductance, and ratio of leaf area to sapwood area were calculated by simplified Whitehead and Jarvis equation, and the effects of tree height on these three parameters were analyzed. The results indicated that under sufficient soil water supply, the whole-tree transpiration increased in a quadratic polynomial way with tree height (P mangium trees had higher reference canopy stomatal conductance and higher sensitivity of canopy stomatal conductance to vapor pressure deficit, compared with the shorter ones. The ratio of leaf area to sapwood area was (1.837 +/- 0.048) m2 x cm(-2), and increased in power function with tree height. A. mangium had no obvious hydraulic limitation and

  6. Water economy of Neotropical savanna trees: six paradigms revisited.

    Science.gov (United States)

    Goldstein, Guillermo; Meinzer, Frederick C; Bucci, Sandra J; Scholz, Fabian G; Franco, Augusto C; Hoffmann, William A

    2008-03-01

    Biologists have long been puzzled by the striking morphological and anatomical characteristics of Neotropical savanna trees which have large scleromorphic leaves, allocate more than half of their total biomass to belowground structures and produce new leaves during the peak of the dry season. Based on results of ongoing interdisciplinary projects in the savannas of central Brazil (cerrado), we reassessed the validity of six paradigms to account for the water economy of savanna vegetation. (1) All savanna woody species are similar in their ability to take up water from deep soil layers where its availability is relatively constant throughout the year. (2) There is no substantial competition between grasses and trees for water resources during the dry season because grasses exclusively explore upper soil layers, whereas trees access water in deeper soil layers. (3) Tree species have access to abundant groundwater, their stomatal control is weak and they tend to transpire freely. (4) Savanna trees experience increased water deficits during the dry season despite their access to deep soil water. (5) Stomatal conductance of savanna species is low at night to prevent nocturnal transpiration, particularly during the dry season. (6) Savanna tree species can be classified into functional groups according to leaf phenology. We evaluated each paradigm and found differences in the patterns of water uptake between deciduous and evergreen tree species, as well as among evergreen tree species, that have implications for regulation of tree water balance. The absence of resource interactions between herbaceous and woody plants is refuted by our observation that herbaceous plants use water from deep soil layers that is released by deep-rooted trees into the upper soil layer. We obtained evidence of strong stomatal control of transpiration and show that most species exhibit homeostasis in maximum water deficit, with midday water potentials being almost identical in the wet and dry

  7. Tree water dynamics in a drying and warming world: Future tree water dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Grossiord, Charlotte [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Sevanto, Sanna [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Borrego, Isaac [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Chan, Allison M. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Collins, Adam D. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Dickman, Lee T. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Hudson, Patrick J. [Department of Biology, MSC03 202, University of New Mexico, Albuquerque NM 87131-0001 USA; McBranch, Natalie [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Michaletz, Sean T. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Pockman, William T. [Department of Biology, MSC03 202, University of New Mexico, Albuquerque NM 87131-0001 USA; Ryan, Max [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Vilagrosa, Alberto [Fundación CEAM, Joint Research Unit University of Alicante - CEAM, Univ. Alicante, PO Box 99 03080 Alicante Spain; McDowell, Nate G. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA 99352 USA

    2017-06-20

    Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD), stomatal conductance (Gs), hydraulic conductivity (KL) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD, Gs and KL. Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs, FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions.

  8. Biophysical properties and functional significance of stem water storage tissues in Neotropical savanna trees.

    Science.gov (United States)

    F.G. Scholz; S.J. Bucci; G. Goldstein; F.C. Meinzer; A.C. Franco; F. Miralles-Wilhelm

    2007-01-01

    Biophysical characteristics of sapwood and outer parenchyma water storage compartments were studied in stems of eight dominant Brazilian Cerrado tree species to assess the impact of differences in tissue capacitance on whole-plant water relations. Both the sapwood and outer parenchyma tissues played an important role in regulation of internal water deficits of Cerrado...

  9. Water Transport in Trees--An Artificial Laboratory Tree

    Science.gov (United States)

    Susman, K.; Razpet, N.; Cepic, M.

    2011-01-01

    Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

  10. Tolerance to water deficit in young trees of jackfruit and sugar apple Tolerância ao déficit hídrico em plantas jovens de jaqueira e pinheira

    Directory of Open Access Journals (Sweden)

    Bruno Monteiro Rodrigues

    2010-06-01

    Full Text Available The predawn leaf water potential (Ψl, stomatal conductance (g s, CO2 assimilation (A, transpiration (E, chlorophyll a fluorescence and leaf metabolite contents (soluble sugars, proteins and free amino acids of two tropical fruit species grown in a greenhouse were evaluated to determine the effect of induced water stress on young plants. Six month-old jackfruit (Artocarpus heterophyllus Lam. and sugar apple (Annona squamosa L. plants were evaluated in 10.0 L pots after eight days of water withholding, imposed by suspension of irrigation. Jackfruit water status was better than sugar apple. Sugar apple plants showed different daily stomatal behavior when well hydrated, compared to jackfruit plants under the same conditions. The gas exchange of both species showed sensibility to high vapor pressure deficit (VPD. However, under water deficit, photochemical efficiency dropped at midday in both treatments (control and water deficit and both species showed low tolerance to high VPD and light intensity under greenhouse conditions. In contrast, some chlorophyll fluorescence variables showed good photosystem II stability at highest VPD hour (14:00 h. The present results involving carbohydrate metabolic changes revealed an accumulation of soluble sugars; moreover, protein and free amino acid contents in water stressed leaves also increased. These findings suggest an absence of damage to photosynthetic machinery for water deficit period. Jackfruit revealed greater tolerance to water deficit than sugar apple an important feature for commercial crops in northeastern Brazil.A condutância estomática (g s, a assimilação de CO2 (A, a transpiração (E, a fluorescência da clorofila e o conteúdo foliar de (açúcares solúveis, proteínas e aminoácidos livres de duas espécies frutíferas tropicais foram avaliados para determinar o efeito do déficit hídrico induzido sobre as plantas da jaqueira (Artocarpus heterophyllus Lam. e da pinheira (Annona squamosa

  11. Virgin olive oil quality of hedgerow 'Arbequina' olive trees under deficit irrigation.

    Science.gov (United States)

    García, José M; Morales-Sillero, Ana; Pérez-Rubio, Ana G; Diaz-Espejo, Antonio; Montero, Antonio; Fernández, José E

    2017-02-01

    Regulated deficit irrigation (RDI) is used in hedgerow olive orchards to achieve a sustainable balance between water savings, tree vigor and oil production. Its effects on the presence of compounds responsible for the taste of the oil and its nutritional value are controversial. The present 3-year study was conducted in an 'Arbequina' orchard (1667 trees ha-1 ) under a full irrigation (FI) treatment (470.1 mm year-1 of water) and two RDI treatments scaled to replace 60% and 30%, respectively, of FI. The quality parameters, antioxidant contents and volatiles of the extracted virgin olive oil (VOO) were analyzed. In general, oils from the 30% RDI treatment had higher contents of pigments and phenolic compounds, a higher oleic/linoleic ratio and the highest oxidative stability, despite their lower tocopherol content. FI oils showed higher (E)-2-hexenal, 1-penten-3-one, ocimene, E-2-pentenal and pentene dimer contents than 30RDI oils, but lower contents of (E)-2-pentenol and volatile esters. The results of the present study suggest that a RDI strategy supplying 30% of the total irrigation needs induces an increase in natural antioxidants in VOO. Neither yield, nor the rest of the quality parameters were affected by the reduced irrigation. However, abundant autumn precipitation can over-ride these effects of 30% RDI treatment on oil quality. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Studies on water deficits on apical development and panicle ...

    African Journals Online (AJOL)

    Leaf primordium production was severely inhibited by periods of water deficit, with apparent cessation occurring around a dawn water potential of -1.0 MPa. Panicle initiation was delayed according to the duration of water deficit and the period of cessation of leaf primordium production. The duration of growth stages two ...

  13. Effect of progressive water deficit stress on proline accumulation and ...

    African Journals Online (AJOL)

    Water deficit stress is one of the important factors limiting chickpea production in arid and semi-arid regions of West Asia and North Africa. When water deficit stress is imposed, different molecular and biochemical responses take place. This study was carried out to investigate proline accumulation and protein profiles of ...

  14. Water deficit modifies the carbon isotopic composition of lipids, soluble sugars and leaves of Copaifera langsdorffii Desf. (Fabaceae

    Directory of Open Access Journals (Sweden)

    Angelo Albano da Silva Bertholdi

    2017-11-01

    Full Text Available ABSTRACT Water deficit is most frequent in forest physiognomies subjected to climate change. As a consequence, several tree species alter tissue water potential, gas exchange and production of carbon compounds to overcome damage caused by water deficiency. The working hypothesis, that a reduction in gas exchange by plants experiencing water deficit will affect the composition of carbon compounds in soluble sugars, lipids and vegetative structures, was tested on Copaifera langsdorffii. Stomatal conductance, leaf water potential, and CO2 assimilation rate declined after a period of water deficit. After rehydration, leaf water potential and leaf gas exchange did not recover completely. Water deficit resulted in 13C enrichment in leaves, soluble sugars and root lipids. Furthermore, the amount of soluble sugars and root lipids decreased after water deficit. In rehydration, the carbon isotopic composition and amount of root lipids returned to levels similar to the control. Under water deficit, 13C-enriched in root lipids assists in the adjustment of cellular membrane turgidity and avoids damage to the process of water absorption by roots. These physiological adjustments permit a better understanding of the responses of Copaifera langsdorffi to water deficit.

  15. Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter?

    Science.gov (United States)

    Stahl, Clément; Hérault, Bruno; Rossi, Vivien; Burban, Benoit; Bréchet, Claude; Bonal, Damien

    2013-12-01

    Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models.

  16. Genetic analysis of water-deficit response traits in maize.

    Science.gov (United States)

    Ahmad, M; Saleem, M; Ahsan, M; Ahmad, A

    2016-03-28

    A set of sixty inbred lines of maize (Zea mays L.) were screened in the greenhouse at the seedling stage under both normal and water-deficit conditions. Six water deficit-tolerant inbred lines were selected based on root to shoot ratios. These selected lines were crossed in a diallel pattern. The parental, F1, and reciprocal cross plants were planted in a field under both normal and water-deficit conditions. Normal irrigation was applied to the control set, while the water-deficit set received 50% of normal irrigation levels. Analyses of variance of various morpho-physiological parameters identified significant differences among the selected lines under both conditions, indicating the presence of significant genetic variability. Variance components for general combining ability (GCA), specific combining ability (SCA), and reciprocal effects for all the parameters were estimated to determine the relative importance of additive and non-additive or dominance type of gene action. Variance components for GCA were larger than for SCA indicating the preponderance of additive types of gene action for all the traits under study. Hybrids developed from inbred lines W-10 and W-64SP proved to have the best grain yield under normal and water-deficit conditions. Under water-deficit conditions, the best performing cross was B-34 x W-10. Hence, these inbred lines and the hybrids might be of value in future breeding programs.

  17. Chelant-enhanced heavy metals uptake by Eucalyptus trees under controlled deficit irrigation

    Science.gov (United States)

    Fine, Pinchas; Rathod, Paresh; Beriozkin, Anna; Ein-Gal, Oz; Hass, Amir

    2014-05-01

    Enhancement of phytoremediation of heavy metal polluted soils employs organic ligands, aimed to solubilize, phytoextract and translocate metals into the canopy. The use of more persistent chelants (e.g. EDTA) is phasing out due to concerns over their role in the environment. We tested the hypothesis that controlled deficit irrigation (CDI) of the fast growing, salinity resistant Eucalyptus camaldulensis coupled with timely EDTA application enhances sediment phytoremediation while minimizing leaching of metal complexes below the root-zone. This was tested in 220-L lysimeters packed with sand mixed with metals polluted biosolids. One year old trees were brought under CDI with tap or RO water for two growing seasons. EDTA, EDDS and citric acid fertigation at 2 mM started in each May for 2.5-3.5 months, and prescribed soil leaching and sampling of tree leaves started thereafter. While all 3 chelants solubilized biosolids metal in batch extraction (EDDS often being the more efficient), EDTA was the only to increased metal concentrations both in the soil solution and in the Eucalyptus leaves. The average concentrations in the soil solution and in the leaves, in the EDTA vs. control (chelant-free) treatments, all respectively, were: Cd - 200 mg L-1 vs. 1.0, and 67 vs. 21 mg kg-1; Cu: 90 vs. 1.5 mg L-1, and 17 vs. 3.0 mg kg-1; Cr: 4.0 vs. 1.4 mg L-1, and 3.0 vs. 1.0 mg kg-1; Ni: 60 mg L-1 vs. 14, and 20 vs. 6.0 mg kg-1; Pb: >44 vs. 0.1 mg L-1, and 9.0 vs. 1.0 mg kg-1; and Zn: 650 vs. 4.0 mg L-1 and 200 vs. 70 mg kg-1. While EDDS was undetectable in all the leachates, EDTA concentrated to up to 100 mM. At 10 mM soil solution concentration, EDDS half-life in acclimated lysimeter media was 5-11 days and that of EDTA was ≥27-d. The study suggests that sustainable phytostabilization and phytoextraction of heavy metals are achievable under CDI with EDTA augmentation at low dose. This was yet futile with the biodegradable EDDS and citric acid. CDI with RO water further widened

  18. Trend analysis of the water requirements, consumption and deficit

    NARCIS (Netherlands)

    Supit, I.; Diepen, van C.A.; Boogaard, H.L.; Ludwig, F.; Baruth, B.

    2010-01-01

    Recent trends in European seasonal weather conditions and related crop water requirements, crop water consumption and crop water deficits were studied using the Crop Growth Monitoring System of the Joint Research Centre of the European Commission for the period 1976–2005. Soft wheat was selected as

  19. Differential response to water deficit stress in alfalfa ( Medicago ...

    African Journals Online (AJOL)

    The present study was fixed as objective to compare the response to water deficit (33% of field capacity, FC) stress of eight cultivars of Medicago sativa, originating from the Mediterranean basin. Comparison was performed on some key parameters such as growth, relative water content, leaf water potential, MDA tissue ...

  20. Theoretical and empirical evidence for the relationship between stem diameter variations and the water status of mature temperate trees

    Science.gov (United States)

    Dietrich, Lars; Zweifel, Roman; Kahmen, Ansgar

    2017-04-01

    Assessing a trees' water status is essential to evaluate its water status during drought. In particular for mature trees it is extremely difficult to monitor the water status throughout the growing season because of the difficulty of canopy access. Daily variations of stem diameter (SDV) are discussed to provide a powerful alternative in measuring a trees' water status. SDV have been shown to incorporate both radial growth and the diurnal shrinkage and swelling of bark tissue, which is caused by daytime transpiration and nighttime refilling, respectively. During dry periods, bark tissue that is depleted in water cannot entirely refill at night resulting in a progressive overall shrinkage of the tree's stem diameter often called tree water deficit (TWD). Comprehensive comparisons of SDV-based values for TWD and reliable values of stem water potential are yet missing for mature trees. As such, TWD has not yet been fully established as a simple and continuous proxy for a trees' water status. Using a canopy crane situated in Northern Switzerland, we calculated TWD based on SDV for six Central European forest tree species during one moist (2014) and one exceptionally dry (2015) growing season and compared these values to the trees' branch water potential. We found a tight relationship between branch water potential and TWD in all six species. We further employed four different mathematical approaches to calculate TWD and tested what approach yielded the best relationship with water potential. Most approaches resulted in significant relationships (p logistic functions. We propose that, based on such a function, TWD can be employed to estimate stem water potential of trees for an entire growing season. We conclude from our data that TWD is tightly correlated to the stem water potential of mature tree species and can, thus, be used to describe continuous seasonal variations in a tree's water status. Because of its relatively easy application and deployment, there is high

  1. Climatic correlates of tree mortality in water- and energy-limited forests.

    Directory of Open Access Journals (Sweden)

    Adrian J Das

    Full Text Available Recent increases in tree mortality rates across the western USA are correlated with increasing temperatures, but mechanisms remain unresolved. Specifically, increasing mortality could predominantly be a consequence of temperature-induced increases in either (1 drought stress, or (2 the effectiveness of tree-killing insects and pathogens. Using long-term data from California's Sierra Nevada mountain range, we found that in water-limited (low-elevation forests mortality was unambiguously best modeled by climatic water deficit, consistent with the first mechanism. In energy-limited (high-elevation forests deficit models were only equivocally better than temperature models, suggesting that the second mechanism is increasingly important in these forests. We could not distinguish between models predicting mortality using absolute versus relative changes in water deficit, and these two model types led to different forecasts of mortality vulnerability under future climate scenarios. Our results provide evidence for differing climatic controls of tree mortality in water- and energy-limited forests, while highlighting the need for an improved understanding of tree mortality processes.

  2. Management of postharvest deficit irrigation of peach trees using infrared canopy temperature

    Science.gov (United States)

    Remotely-sensed canopy temperature from infrared thermometer (IRT) sensors has long been shown effective for detecting plant water stress, a vadose zone problem for growing plants. To help alleviate water shortage in the San Joaquin Valley of California, deficit irrigation may be used where the tar...

  3. Tree water dynamics in a drying and warming world.

    Science.gov (United States)

    Grossiord, Charlotte; Sevanto, Sanna; Borrego, Isaac; Chan, Allison M; Collins, Adam D; Dickman, Lee T; Hudson, Patrick J; McBranch, Natalie; Michaletz, Sean T; Pockman, William T; Ryan, Max; Vilagrosa, Alberto; McDowell, Nate G

    2017-09-01

    Disentangling the relative impacts of precipitation reduction and vapour pressure deficit (VPD) on plant water dynamics and determining whether acclimation may influence these patterns in the future is an important challenge. Here, we report sap flux density (FD ), stomatal conductance (Gs ), hydraulic conductivity (KL ) and xylem anatomy in piñon pine (Pinus edulis) and juniper (Juniperus monosperma) trees subjected to five years of precipitation reduction, atmospheric warming (elevated VPD) and their combined effects. No acclimation occurred under precipitation reduction: lower Gs and FD were found for both species compared to ambient conditions. Warming reduced the sensibility of stomata to VPD for both species but resulted in the maintenance of Gs and FD to ambient levels only for piñon. For juniper, reduced soil moisture under warming negated benefits of stomatal adjustments and resulted in reduced FD , Gs and KL . Although reduced stomatal sensitivity to VPD also occurred under combined stresses, reductions in Gs , FD and KL took place to similar levels as under single stresses for both species. Our results show that stomatal conductance adjustments to high VPD could minimize but not entirely prevent additive effects of warming and drying on water use and carbon acquisition of trees in semi-arid regions. © 2017 John Wiley & Sons Ltd.

  4. Effects of regulated deficit irrigation on physiology, yield and fruit quality in apricot trees under Mediterranean conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Sarmiento, F.; Mirás-Avalos, J.M.; Alcobendas, R.; Alarcón, J.J.; Mounzer, O.; Nicolas, E.

    2016-07-01

    Scarce water resources mainly in arid and semi-arid areas have caused an increasing interest for applying irrigation protocols aiming to reduce water spends. The effects of regulated deficit irrigation (RDI) on the performance of apricot trees (Prunus armeniaca L. cv. “Búlida”) were assessed in Murcia (SE Spain), during three consecutive growing seasons (2008-2010). The hypothesis was that RDI would not restrict yield but increase fruit quality while saving water. Two irrigation treatments were established: i) control, irrigated to fully satisfy crop water requirements (100% ETc) and ii) RDI, that reduced the amount of applied water to: a) 40% of ETc at flowering and stage I of fruit growth; b) 60% of ETc during the stage II of fruit growth and c) 50% and 25% of ETc during the late postharvest period (from 60 days after harvest). Stem water potential, gas exchanges, trunk cross-sectional area (TCSA), fruit diameter, yield and fruit quality traits were determined. Vegetative growth was decreased by the use of RDI (12% less TCSA on average for the three years), whereas yield was unaffected. In addition, some qualitative characteristics of the fruits, such as the level of soluble solids, sweetness/acidity relation and fruit colour, were improved by the use of RDI. These results and average water savings of approximately 30%, lead us to conclude that RDI strategies are a possible solution for irrigation management in areas with water shortages, such as arid and semi-arid environments.

  5. Effect of Water Deficit Stress on Peach Growth under Commercial Orchard Management Conditions

    Directory of Open Access Journals (Sweden)

    M. Rahmati

    2015-06-01

    Full Text Available In order to study the sensitivity of vegetative growth to water deficit stress of a late-maturing peach (Prunus persica L. cv. Elberta under orchard conditions, an experiment was conducted as randomized complete-block design with three treatments and four repetitions in Shahdiran commercial orchard in Mashhad during 2011. Three irrigation treatments including 360 (low stress, 180 (moderate stress and 90 (severe stress m3ha-1week-1 using a drip irrigation system (minimum stem water potential near harvest: -1.2, -1.5 and -1.7 MPa, respectively from the mid-pit hardening stage (12th of June until harvest (23rd of Sep. applied. Predawn, stem and leaf water potentials, leaf photosynthesis, transpiration, stomatal conductance and leaf temperature, the number of new shoots on fruit bearing shoots and vegetative shoots lengths during growing season as well as leaf area at harvest were measured. The results showed that water deficit stress had negative effects on peach tree water status, thereby resulting in decreased leaf gas exchange and tree vegetative growth. As significant decreased assimilate production of tree was resulted from both decreased leaf assimilation rate (until about 23 % and 50 %, respectively under moderate and severe stress conditions compared to low stress conditions and decreased leaf area of tree (until about 57% and 79%, respectively under moderate and severe stress conditions compared to low stress conditions at harvest. The significant positive correlation between leaf water potential and vegetative growth of peach revealed that shoot growth would decrease by 30% and 50% of maximum at leaf water potential of –1.56 and –2.30 MPa, respectively.

  6. Responses of Six Wheat Cultivars to Terminal Water Deficit

    Directory of Open Access Journals (Sweden)

    M. Behrozi

    2015-12-01

    Full Text Available In order to evaluate the morpho-physiological and biochemical responses of six wheat (Triticum aestivum L. cultivars to late season water deficit stress, this experiment was carried out in controlled conditions at College of Agriculture of Shiraz University, Shiraz, Iran during 2013-14. The experimental treatments were water deficit (50 and 100% F.C. and wheat cultivars (Sirvan, Chamran, Shiraz, Marvdasht, Hamoun, Pishtaz. The results showed that water deficit significantly reduced flag leaf area (7.23%, number of grains per spike (17.37%, 1000 grain weight (20.88%, grain yield (17.73%, biological yield (15%, and harvest index (10.75% and increased the chlorophyll content (14.48% in all wheat cultivars. Significant differences were found in physiological responses among wheat cultivars. Under water deficit stress, Sirvan and Chamran cultivars had significantly higher growth and yield compared to other wheat cultivars. Water stress increased the activity of catalase, peroxidase and superoxide dismutase and this increase was significantly higher in Sirvan and Chamran cultivars. It could be concluded that in Sirvan and Chamran cultivars the increased antioxidants activities led to the partial amelioration of the adverse effects of water deficit, resulting in greater grain yield and yield components, compared to the remaining genotypes.

  7. Effect of Water Deficit Stress on the Physiology, Growth and Leaf ...

    African Journals Online (AJOL)

    The three water deficit levels were created by adding 0, 10 and 20% (w/v) polyethylene glycol 6000 (PEG 6000) to the nutrient solution. The results indicated that water deficit, especially severe water deficit (-0.96 MPa), severely affected the growth and physiology of sorghum. Water deficit stress reduced plant height, leaf ...

  8. The influence of drought on the water uptake by Scots pines (Pinus sylvestris L. at different positions in the tree stand

    Directory of Open Access Journals (Sweden)

    Boczoń Andrzej

    2015-12-01

    Full Text Available Periodically occurring drought is typical for the climate of Poland. In habitats supplied exclusively with rain water, tree stands are frequently exposed to the negative effects of water deficit in the soil. The aim of this study was to examine the water uptake and consumption of two individual Scots pine trees under drought conditions. The trees were located at different positions within the stand and at the time of study were over 150 years old. Soil moisture, availability of soil water and the quantity of water uptake by the individual trees were examined by measuring the water velocity inside the trunks (Thermal Dissipation Probe method.

  9. Chelant-enhanced heavy metal uptake by Eucalyptus trees under controlled deficit irrigation.

    Science.gov (United States)

    Fine, Pinchas; Paresh, Rathod; Beriozkin, Anna; Hass, Amir

    2014-09-15

    We tested the hypothesis that controlled deficit irrigation (CDI) of the fast growing, salinity resistant Eucalyptus camaldulensis tree with timely EDTA application can enhance sediment clean-up while minimizing leaching of metal complexes. 220-L lysimeters containing a sand-metal-polluted sludge mixture. Established saplings were irrigated with tap or desalinized (RO) water with/without 4-times daily addition of EDTA, EDDS and citric acid. In the 2nd season (2008/9) the chelates were added at 2 mM for ≈ 70 summer days. Diagnostic leaves and soil solution compositions were regularly monitored, the latter by applying prescribed leaching at an overall leaching percentage of ≈ 0.4%. While the three chelants solubilized sludge metals in batch extraction, EDDS often being the more efficient chelant, EDTA only was effective in the soil system. Leachate and leaves peak average concentrations in EDTA treatment vs. the control treatments were: Cd: 200 mg L(-1) vs. 1.0 and 67 vs. 21 mg kg(-1); Cu: 90 vs. 1.5 mg L(-1) and 17 vs. 3.0 mg kg(-1); Ni: 60 mg L(-1) vs. 14 and 20 vs. 6.0 mg kg(-1); Pb: >44 vs. 0.1 mg L(-1) and 9.0 vs. 1.0 mg kg(-1); and Zn: 650 vs. 4.0 mg L(-1) and 200 vs. 70 mg kg(-1), all respectively. Peak average leachate EDTA concentration was >60 mM, yet acclimating soil microflora gradually degraded most all the EDTA. In incubation study, EDDS and EDTA half-lives in acclimated lysimeter media were 5-11 days and ≥ 27 days, respectively. It suggests that sustainable phytoextraction of heavy metals is feasible under careful CDI with EDTA (yet not with biodegradable chelants) augmentation at low doses. Despite that the eucalypt was highly salinity (and EDTA) resistant, CDI using RO water further reduces soil solution salinity, thus increasing the usefulness of this remediation technique. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Influence of Irrigation Scheduling Using Thermometry on Peach Tree Water Status and Yield under Different Irrigation Systems

    Directory of Open Access Journals (Sweden)

    Huihui Zhang

    2017-02-01

    Full Text Available Remotely-sensed canopy temperature from infrared thermometer (IRT sensors has long been shown to be effective for detecting plant water stress. A field study was conducted to investigate peach tree responses to deficit irrigation which was controlled using canopy to air temperature difference (ΔT during the postharvest period at the USDA-ARS (U.S. Department of Agriculture, Agricultural Research Service San Joaquin Valley Agricultural Sciences Center in Parlier, California, USA. The experimental site consisted of a 1.6 ha early maturing peach tree orchard. A total of 18 IRT sensors were used to control six irrigation treatments including furrow, micro-spray, and surface drip irrigation systems with and without postharvest deficit irrigation. During the postharvest period in the 2012–2013 and 2013–2014 growing seasons, ΔT threshold values at mid-day was tested to trigger irrigation in three irrigation systems. The results showed that mid-day stem water potentials (ψ for well irrigated trees were maintained at a range of −0.5 to −1.2 MPa while ψ of deficit irrigated trees dropped to lower values. Soil water content in deficit surface drip irrigation treatment was higher compared to deficit furrow and micro-spray irrigation treatments in 2012. The number of fruits and fruit weight from peach trees under postharvest deficit irrigation treatment were less than those well-watered trees; however, no statistically significant (at the p < 0.05 level reduction in fruit size or quality was found for trees irrigated by surface drip and micro-spray irrigation systems by deficit irrigation. Beside doubles, we found an increased number of fruits with deep sutures and dimples which may be a long-term (seven-year postharvest regulated deficit irrigation impact of deficit irrigation on this peach tree variety. Overall, deployment of IRT sensors provided real-time measurement of canopy water status and the information is valuable for making irrigation

  11. Transcriptome profiling of tobacco under water deficit conditions

    Directory of Open Access Journals (Sweden)

    Roel C. Rabara

    2015-09-01

    Full Text Available Drought is one of the limiting environmental factors that affect crop production. Understanding the molecular basis of how plants respond to this water deficit stress is key to developing drought tolerant crops. In this study we generated time course-based transcriptome profiles of tobacco plants under water deficit conditions using microarray technology. In this paper, we describe in detail the experimental procedures and analyses performed in our study. The data set we generated (available in the NCBI/GEO database under GSE67434 has been analysed to identify genes that are involved in the regulation of tobacco's responses to drought.

  12. Peach water relations, gas exchange, growth and shoot mortality under water deficit in semi-arid weather conditions.

    Science.gov (United States)

    Rahmati, Mitra; Davarynejad, Gholam Hossein; Génard, Michel; Bannayan, Mohammad; Azizi, Majid; Vercambre, Gilles

    2015-01-01

    In this study the sensitivity of peach tree (Prunus persica L.) to three water stress levels from mid-pit hardening until harvest was assessed. Seasonal patterns of shoot and fruit growth, gas exchange (leaf photosynthesis, stomatal conductance and transpiration) as well as carbon (C) storage/mobilization were evaluated in relation to plant water status. A simple C balance model was also developed to investigate sink-source relationship in relation to plant water status at the tree level. The C source was estimated through the leaf area dynamics and leaf photosynthesis rate along the season. The C sink was estimated for maintenance respiration and growth of shoots and fruits. Water stress significantly reduced gas exchange, and fruit, and shoot growth, but increased fruit dry matter concentration. Growth was more affected by water deficit than photosynthesis, and shoot growth was more sensitive to water deficit than fruit growth. Reduction of shoot growth was associated with a decrease of shoot elongation, emergence, and high shoot mortality. Water scarcity affected tree C assimilation due to two interacting factors: (i) reduction in leaf photosynthesis (-23% and -50% under moderate (MS) and severe (SS) water stress compared to low (LS) stress during growth season) and (ii) reduction in total leaf area (-57% and -79% under MS and SS compared to LS at harvest). Our field data analysis suggested a Ψstem threshold of -1.5 MPa below which daily net C gain became negative, i.e. C assimilation became lower than C needed for respiration and growth. Negative C balance under MS and SS associated with decline of trunk carbohydrate reserves--may have led to drought-induced vegetative mortality.

  13. Response mechanisms of Brachiaria brizantha cultivars to water deficit stress

    Directory of Open Access Journals (Sweden)

    Patricia Menezes Santos

    2013-11-01

    Full Text Available Two cultivars of Brachiaria brizantha (Hochst ex. A. Rich Stapf. (Syn. Urochloa were evaluated for their adaptation to water deficit and the stress response mechanisms in a greenhouse experiment. The experimental design was in completely randomized blocks with a 2 × 2 × 4 factorial arrangement. The Marandu and BRS Piatã cultivars were evaluated under two water availability conditions, with or without water restriction. The harvests were carried out 0, 7, 14 and 28 days after the start of water restriction. For both cultivars, the water deficit stress caused a reduction in shoot biomass and leaf area and an increase in the percentage of roots in the deeper soil layers. The B. brizantha cv. Marandu reached critical levels of leaf water potential in a shorter period of water restriction than did the B. brizantha cv. BRS Piatã. The osmoregulation and deepening of the root system are mechanisms of adaptation to water stress observed in both Marandu and BRS Piatã cultivars. Besides that, the Marandu cultivar also increases its leaf senescence and, consequentially, decreases its leaf area, as a response to water deficit.

  14. Effect of root pruning and irrigation regimes on leaf water relations and xylem ABA and ionic concentrations in pear trees

    DEFF Research Database (Denmark)

    Wang, Yufei; Bertelsen, Marianne G.; Petersen, Karen Koefoed

    2014-01-01

    pruning caused water deficit stress in pear trees. Further RP trees had significantly lower concentrations of total cations and anions and the sum of cations and anions than the NP trees implying root pruning decreased acquisition of nutrients from the soil. In the root pruned trees, the leaf water......Root pruning is an effective approach for controlling vegetative growth of pear trees (Pyrus communis L.), yet the underlying mechanisms for such effect remain largely elusive. A two-year field experiment was conducted to investigate the effect of root pruning and irrigation regimes on leaf water...... relation characteristics, stomatal conductance and xylem sap abscisic acid (ABA) and ionic concentrations. Results showed that leaf water potential, leaf turgor and stomatal conductance of root pruning (RP) treatment was significantly lower than those of non-root pruning (NP) treatment indicating that root...

  15. Water-tree resistant cable formulations

    Energy Technology Data Exchange (ETDEWEB)

    Sarma, H.; Dobbin, C.J.B.

    1992-10-06

    Polyethylene compositions are disclosed which are suitable for use as cable insulation for high voltage power distribution cables and, more particularly, contain an additive to inhibit the propagation of water trees in the insulation. The polyethylene composition of the invention is obtained by cross-linking a composition comprising ca 95 wt % of a low-density crosslinkable polyethylene and at least 1 wt % of a hydrolyzed terpolymer of ethylene, vinyl acetate, and vinyl alcohol. The terpolymer is obtained from the at least 95% hydrolysis of an ethylene-vinyl acetate copolymer having a 20-30 wt % vinyl acetate content. The polyethylene and the terpolymer have a substantially similar melt index. Tests conducted to evaluate insulation compositions of the invention are described. 1 fig., 4 tabs.

  16. Morph-physiological responses to water deficit in parental ...

    African Journals Online (AJOL)

    Morph-physiological responses to water deficit in parental genotypes of Medicago truncatula recombinant inbred lines. ... High to moderate broad-sense heritability (H²) were observed for most of the traits under control treatment and drought stress. Most of the correlations between measured traits were positive under the ...

  17. Genetic variation of response to water deficit in parental genotypes ...

    African Journals Online (AJOL)

    dgomi

    Key words: M. truncatula, parental lines, recombinant inbred lines, water deficit, morphological traits, photosynthetic parameters. ... changes in the structure of plants (Shao et al., 2008), the growth rate and gas exchange at the leaf ... due to decreased CO2 concentrations at the chloroplast level (Cornic, 1994). Furthermore ...

  18. Soybean response to nitrogen fertilizer under water deficit conditions

    African Journals Online (AJOL)

    user

    2011-04-18

    Apr 18, 2011 ... In order to determine the effect of water deficit and nitrogen fertilizer application on growth indices, yield and yield component of three soybean (Glycine Max L. Merr) genotypes a split plot factorial experiment based on randomized complete block with three replications was carried out. Soybean genotypes ...

  19. Effect of water deficit on growth and photosynthetic characteristics of ...

    African Journals Online (AJOL)

    Water deficit decreased total leaf area, above-ground biomass, net photosynthesis, stomatal conductance, internal CO2 concentration and the actual quantum yield of PS II electron transport relative to cultivars that were grown under control condition. Measurement of stomatal conductance provided useful information to ...

  20. Effects of short-term water deficit stress on physiological ...

    African Journals Online (AJOL)

    South African Journal of Plant and Soil ... However, there is limited information on the ways Bambara groundnut landraces respond and adapt to drought. The study was conducted to evaluate the response of Bambara groundnut landraces sourced from contrasting environments to periods of water deficit initiated at ...

  1. Genetic variation of response to water deficit in parental genotypes ...

    African Journals Online (AJOL)

    dgomi

    2016-06-22

    Jun 22, 2016 ... changes in the structure of plants (Shao et al., 2008), the growth rate and ... of water deficit on photosynthetic and growth charac- teristics in ... weight was obtained after oven-drying leaf, stem and root samples at 60ºC for 48 h.

  2. Soybean response to nitrogen fertilizer under water deficit conditions

    African Journals Online (AJOL)

    In order to determine the effect of water deficit and nitrogen fertilizer application on growth indices, yield and yield component of three soybean (Glycine Max L. Merr) genotypes a split plot factorial experiment based on randomized complete block with three replications was carried out. Soybean genotypes (Williams, K1410 ...

  3. Threshold Responses to Soil Moisture Deficit by Trees and Soil in Tropical Rain Forests: Insights from Field Experiments

    Science.gov (United States)

    Meir, Patrick; Wood, Tana E.; Galbraith, David R.; Brando, Paulo M.; Da Costa, Antonio C. L.; Rowland, Lucy; Ferreira, Leandro V.

    2015-01-01

    Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported for tropical rain forests. We examine them, synthesizing key results and focusing on two processes that have shown threshold behavior in response to drought: (1) tree mortality and (2) the efflux of carbon dioxdie from soil, soil respiration. We show that: (a) where tested using large-scale field experiments, tropical rain forest tree mortality is resistant to long-term soil moisture deficit up to a threshold of 50% of the water that is extractable by vegetation from the soil, but high mortality occurs beyond this value, with evidence from one site of increased autotrophic respiration, and (b) soil respiration reaches its peak value in response to soil moisture at significantly higher soil moisture content for clay-rich soils than for clay-poor soils. This first synthesis of tropical TFE experiments offers the hypothesis that low soil moisture–related thresholds for key stress responses in soil and vegetation may prove to be widely applicable across tropical rain forests despite the diversity of these forests. PMID:26955085

  4. Modelling soil water dynamics of full and deficit drip irrigated maize cultivated under a rain shelter

    OpenAIRE

    González, Maria G.; Ramos, Tiago B.; Carlesso,Reimar; Paredes, Paula; Petry,Mirta T.; Martins, Juliano D.; Aires, Núbia P.; L. S. Pereira

    2015-01-01

    Research Paper The model HYDRUS-1D was used to simulate soil water dynamics of full and deficit irrigated maize grown under a rainout shelter during two crop seasons. Four irrigation treatments were established based on the amount of water applied to fulfil crop water requirements. Treatment D1 was irrigated to fully satisfy crop water requirements, while treatments D2 (mild deficit), D3 (moderate deficit), and D4 (severe deficit) were for increased controlled water stress c...

  5. Predicting water suppy and actual evapotranspiration of street trees

    Science.gov (United States)

    Wessolek, Gerd; Heiner, Moreen; Trinks, Steffen

    2017-04-01

    It's well known that street trees cool air temperature in summer-time by transpiration and shading and also reduce runoff. However, it's difficult to analyse if trees have water shortage or not. This contribution focus on predicting water supply, actual evapotranspiration, and runoff by using easily available climate data (precipiation, potential evapotranspiration) and site characteristics (water retention, space, sealing degree, groundwater depth). These parameter were used as input data for Hydro-Pedotransfer-Functions (HPTFs) allowing the estimation of the annual water budget. Results give statements on water supply of trees, drought stress, and additional water demand by irrigation. Procedure also analyse, to which extent the surrounding partly sealed surfaces deliver water to the trees. Four representative street canyons of Berlin City were analysed and evaluated within in training program for M.A. students of „Urban Eco-system Science" at the Technische Universität Berlin.

  6. The effect of water deficit on body temperature during rugby.

    Science.gov (United States)

    Cohen, I; Mitchell, D; Seider, R; Kahn, A; Phillips, F

    1981-07-04

    Sweat losses, water deficits and changes in rectal temperature were measured in 13 first-league players during a rugby match. Changes in plasma volume, serum electrolyte and blood glucose levels were also determined. Rectal temperatures were markedly elevated after the match. Both temperatures reached levels which are known to be associated with an impairment of physical, mental and psychological function, and could have caused a deterioration in performance during the second half of the match. Body temperatures were high enough to have predisposed to aggressive behaviour. Increases in rectal temperature were related to water deficit. The small volumes of fluid ingested by the players just before and during the match suggest that they are unaware of the importance of preventing dehydration. Recommendations are made to reduce the risk of hyperthermia. Glucose and electrolyte supplementation is not required just before and during rugby.

  7. Vapor-pressure deficit and extreme climatic variables limit tree growth.

    Science.gov (United States)

    Sanginés de Cárcer, Paula; Vitasse, Yann; Peñuelas, Josep; Jassey, Vincent E J; Buttler, Alexandre; Signarbieux, Constant

    2017-11-03

    Assessing the effect of global warming on forest growth requires a better understanding of species-specific responses to climate change conditions. Norway spruce and European beech are among the dominant tree species in Europe and are largely used by the timber industry. Their sensitivity to changes in climate and extreme climatic events, however, endangers their future sustainability. Identifying the key climatic factors limiting their growth and survival is therefore crucial for assessing the responses of these two species to ongoing climate change. We studied the vulnerability of beech and spruce to warmer and drier conditions by transplanting saplings from the top to the bottom of an elevational gradient in the Jura Mountains in Switzerland. We (1) demonstrated that a longer growing season due to warming could not fully account for the positive growth responses, and the positive effect on sapling productivity was species-dependent, (2) demonstrated that the contrasting growth responses of beech and spruce were mainly due to different sensitivities to elevated vapor-pressure deficits (VPD), (3) determined the species-specific limits to VPD above which growth rate began to decline, and (4) demonstrated that models incorporating extreme climatic events could account for the response of growth to warming better than models using only average values. These results support that the sustainability of forest trees in the coming decades will depend on how extreme climatic events will change, irrespective of the overall warming trend. © 2017 John Wiley & Sons Ltd.

  8. Linking Plant Water-Use Efficiency and Depth of Water Uptake to Field­-Level Productivity Under Surplus and Deficit Irrigation in Almond Orchards

    Science.gov (United States)

    Seely, T.; Shackel, K.; Silva, L. C. R.

    2016-12-01

    The impact of water stress on depth of water uptake, as well as water­-use efficiency (WUE) at the tree-level and field-level was examined in almond orchards under varying degrees of deficit and surplus irrigation treatments. Three different orchards, spanning a latitudinal gradient (35° to 39° N) were sampled during two growing seasons in the central valley of CA. The orchards encompass a range of climatic and edaphic conditions, providing an opportunity for comparisons of WUE and orchard yield under contrasting environmental conditions. In each orchard, the control treatment received 100% replacement of water lost to evapotranspiration (ET), while the surplus treatment received 110% and the deficit treatment received 70% replenishment of ET, the latter simulating conditions of water stress. Preliminary results based on the analysis of carbon isotope ratios (δ13C) in leaves throughout the 2015 and 2016 growing seasons, reveal a significant change in WUE in all three orchard sites, increasing up to 20% on average in the deficit irrigation treatment relative to controls. In contrast, trees growing under surplus irrigation had the lowest WUE across all orchard sites. The difference in WUE between surplus irrigated trees and control irrigated trees within each orchard was not always statistically significant. These physiological responses to levels of water availability were not reflected in field-level orchard productivity, which was highly variable across orchard sites and treatments. Additionally, analysis of oxygen (δ18O) and hydrogen (δ2H) isotope ratios of stem, leaf, and soil water has been undertaken to determine the effect of water stress on the depth of root water uptake. The hypothesis that almond trees can effectively acclimate to water stress through higher WUE and deeper root water uptake compared to well-watered trees will be tested. This multi-scale, ecohydrological study will elucidate the impacts of drought on almond orchards, one of the most

  9. Water deficit treatment and measurement in apple trees

    Science.gov (United States)

    Simulating drought can be a complex undertaking involving different strategies and methodologies many of which are not appropriate for perennial plants and often do not reflect what the plants face under field conditions. We developed a protocol for woody plants that approaches field drought situat...

  10. Response of Eucalyptus grandis trees to soil water deficits

    CSIR Research Space (South Africa)

    Dye, PJ

    1996-01-01

    Full Text Available time (cf. Dunin and Aston 1984, Calder 1992). Materials and methods Site descriptions and treatments Two experimental sites were chosen in Frankfort State Forest (24°49′ S, 30°43′ E) in the Mpumalanga (formerly Eastern Transvaal) province of South..., and the size of the wound at each probe set location was measured (to the nearest 0.1 mm) with a 7X scale loupe. The wound measure- ments were taken midway between the line heater position and both the upper and lower thermistors. Swanson and Whitfield’s...

  11. Plant genetic and molecular responses to water deficit

    Directory of Open Access Journals (Sweden)

    Silvio Salvi

    2011-02-01

    Full Text Available Plant productivity is severely affected by unfavourable environmental conditions (biotic and abiotic stresses. Among others, water deficit is the plant stress condition which mostly limits the quality and the quantity of plant products. Tolerance to water deficit is a polygenic trait strictly dependent on the coordinated expression of a large set of genes coding for proteins directly involved in stress-induced protection/repair mechanisms (dehydrins, chaperonins, enzymes for the synthesis of osmoprotectants and detoxifying compounds, and others as well as genes involved in transducing the stress signal and regulating gene expression (transcription factors, kinases, phosphatases. Recently, research activities in the field evolved from the study of single genes directly involved in cellular stress tolerance (functional genes to the identification and characterization of key regulatory genes involved in stress perception and transduction and able to rapidly and efficiently activate the complex gene network involved in the response to stress. The complexity of the events occurring in response to stress have been recently approached by genomics tools; in fact the analysis of transcriptome, proteome and metabolome of a plant tissue/cell in response to stress already allowed to have a global view of the cellular and molecular events occurring in response to water deficit, by the identification of genes activated and co-regulated by the stress conditions and the characterization of new signalling pathways. Moreover the recent application of forward and reverse genetic approaches, trough mutant collection development, screening and characterization, is giving a tremendous impulse to the identification of gene functions with key role in stress tolerance. The integration of data obtained by high-throughput genomic approaches, by means of powerful informatic tools, is allowing nowadays to rapidly identify of major genes/QTLs involved in stress tolerance

  12. Irrigation scheduling of grapefruit trees in a Mediterranean environment throughout evaluation of plant water status and evapotranspiration

    OpenAIRE

    ÜNLÜ, Mustafa; KANBER, Rıza; KOÇ, D. Levent; ÖZEKİCİ, Bülent; KEKEÇ, Uğur

    2014-01-01

    In this study, 1 full irrigation regime (100% of crop evapotranspiration, I100) and 2 deficit irrigation regimes (70%, I70, and 50%, I50) were evaluated in a Rio Red grapefruit (Citrus paradisi Macfad. 'Rio Red') orchard in Adana, Turkey. Fruit yield, leaf water potential (LWP), and soil water depletion (SWD) were measured among trees from each treatment. Actual evapotranspiration was calculated in 3 ways, using 2 energy balance methods (eddy correlation and Bowen&am...

  13. Deficit

    CERN Multimedia

    2002-01-01

    UCL's former provost, Sir Derek Roberts, has been drafted in for a year to run the college. UCL is expected to have a 6 million pounds deficit this year and up to a 10 million pounds deficit next year. Sir Christopher Llewellyn-Smith took over at UCL nearly 4 years ago and decided then that the finanical situation was serious enough to warrant a reduction in the vast expansion policy undertaken by his predecessor (1 page).

  14. Effects of regulated deficit irrigation during the pre-harvest period on gas exchange, leaf development and crop yield of mature almond trees.

    Science.gov (United States)

    Romero, Pascual; Navarro, Josefa Maria; García, Francisco; Botía Ordaz, Pablo

    2004-03-01

    We investigated the effects of regulated deficit irrigation (RDI) during the pre-harvest period (kernel-filling stage) on water relations, leaf development and crop yield in mature almond (Prunus dulcis (Mill.) D.A. Webb cv. Cartagenera) trees during a 2-year field experiment. Trees were either irrigated at full-crop evapotranspiration (ETc=100%) (well-irrigated control treatment) or subjected to an RDI treatment that consisted of full irrigation for the full season, except from early June to early August (kernel-filling stage), when 20% ETc was applied. The severity of water stress was characterized by measurements of soil water content, predawn leaf water potential (Psipd) and relative water content (RWC). Stomatal conductance (gs), net CO2 assimilation rate (A), transpiration rate (E), leaf abscission, leaf expansion rate and crop yield were also measured. In both years, Psipd and RWC of well-irrigated trees were maintained above -1.0 MPa and 92%, respectively, whereas the corresponding values for trees in the RDI treatment were -2.37 MPa and 82%. Long-term water stress led to a progressive decline in gs, A and E, with significant reductions after 21 days in the RDI treatment. At the time of maximum stress (48 days after commencement of RDI), A, gs and E were 64, 67 and 56% lower than control values, respectively. High correlations between A, E and gs were observed. Plant water status recovered within 15 days after the resumption of irrigation and was associated with recovery of soil water content. A relatively rapid and complete recovery of A and gs was also observed, although the recovery was slower than for Psipd and RWC. Severe water stress during the kernel-filling stage resulted in premature defoliation (caused by increased leaf abscission) and a reduction in leaf growth rate, which decreased tree leaf area. Although kernel yield was correlated with leaf water potential, RDI caused a nonsignificant 7% reduction in kernel yield and had no effect on kernel

  15. Cross-scale interactions affect tree growth and intrinsic water ...

    Science.gov (United States)

    1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes (13C) to investigate the impacts of thinning across a range of progressively finer spatial scales: site, stand, hillslope position, and neighborhood position. In particular, we focused on the influence of thinning beyond the boundaries of thinned stands to include impacts on downslope and neighboring stands across sites varying in soil moisture. 3. Trees at the wet site responded to thinning with increased growth when compared with trees at the dry site. Additionally, trees in thinned stands at the dry site responded with increased iWUE while trees in thinned stands at the wet site showed no difference in iWUE compared to unthinned stands. 4. We hypothesized that water is not the primary limiting factor for growth at our sites, but that thinning released other resources, such as growing space or nutrients to drive the growth response. At progressively finer spatial scales we found that the responses of trees was not driven by hillslope location (i.e., downslope of thinning) but to changes in local neighborhood tree density. 5. The results of this study demonstrated that water can be viewed as an “agent” that allows us to investigate cross-scale interactions as it links coarse to finer spatial scales and vice ver

  16. Soil moisture and wild olive tree transpiration relationship in a water-limited Mediterranean ecosystem.

    Science.gov (United States)

    Curreli, M.; Montaldo, N.; Oren, R.

    2016-12-01

    Typically, during the dry summers, Mediterranean ecosystems are characterized by a simple dual PFTs system with strong-resistant woody vegetation and bare soil, since grass died. In these conditions the combined use of sap flow measurements, based on Granier's thermo-dissipative probes, eddy covariance technique and soil water content measurements provides a robust estimation of evapotranspiration (ET). An eddy covariance micrometeorological tower, thermo-dissipative probes based on the Granier technique and TDR sensors have been installed in the Orroli site in Sardinia (Italy). The site landscape is a mixture of Mediterranean patchy vegetation types: wild olives, different shrubs and herbaceous species, which died during the summer. 33 sap flow sensors have been installed at the Orroli site into 15 wild olives clumps with different characteristics (tree size, exposition to wind, solar radiation and soil depth). Sap flow measurements show the significantly impacts on transpiration of soil moisture, radiation and vapor pressure deficit (VPD). In addition ET is strongly influenced by the tree position into the clump. Results show a significant difference in sap flow rate for the south exposed trees compared to inside clump and north exposed trees. Using an innovative scaling procedure, the transpiration calculated from sap flow measurements have been compared to the eddy covariance ET. Sap flow measurements show night time uptake allows the recharge of the stem capacity, depleted during the day before due to transpiration. The night uptake increases with increasing VPD and transpiration but surprisingly it is independent to soil water content. Soil moisture probes allow monitoring spatial and temporal dynamics of water content at different soil depth and distance to the trees, and estimating its correlation with hydraulic lift. During the light hours soil moisture is depleted by roots to provide the water for transpiration and during night time the lateral roots

  17. Tree Water Use May Significantly Impact Boreal Hydrology

    Science.gov (United States)

    Young, J. M.; Bolton, W. R.

    2013-12-01

    The ecohydrology of boreal forest ecosystems of Interior Alaska is not well understood largely because of challenges posed by the presence of discontinuous permafrost. Near-surface permafrost results in storage-dominated systems with cold, poorly drained soils, and slow growing, low statured coniferous trees (Picea mariana) or CDE's. The transition to permafrost-free areas can occur over a few meters and is accompanied by a vegetation community dominated by large deciduous trees (Populus sp. and Betula sp.) or DDE's. Typically, areas with permafrost are on north facing slopes and valley bottoms, and areas without permafrost are south facing. In Alaska's boreal forest, the permafrost is very warm and vulnerable to the effects of climate change. Once permafrost begins to thaw, the vegetation community shifts from coniferous to deciduous dominated. Streamflow in watersheds with a larger permafrost distribution tends to be higher and more responsive to precipitation events than in watersheds with low permafrost distribution. In fact, precipitation events in the low permafrost areas do not infiltrate past the rooting zone of the deciduous trees (~5-40 cm). This suggests that the deciduous trees may remove water from the system via uptake and transpiration. We focus on how vegetation water use affects boreal forest hydrology in areas of discontinuous permafrost. Specifically, we ask: what are the patterns of vegetation water use in areas with and without permafrost? This study focuses on the CDE and DDE systems. Our research sites are established on low and high locations on each aspect (south facing DDE, north facing CDE) to capture the variability associated with the different hillside drainage properties. At each of the four sites during the growing season, we measured various aspects of plant water use dynamics, including water flux, water content, water sources, depth of water uptake in the soil, and water stress. We use a Bayesian framework to analyze the data. We

  18. The water holding capacity of bark in Danish angiosperm trees

    DEFF Research Database (Denmark)

    Larsen, Hanne Marie Ellegård; Rasmussen, Hanne Nina; Nord-Larsen, Thomas

    2017-01-01

    The water holding capacity of bark in seven Danish angiosperm trees was examined. The aim of the study was (1) to examine height trends and (2) bark thickness trends in relation to the water holding capacity and (3) to determine interspecific differences. The wet-weight and dry-weight of a total...

  19. Productivity, water-use efficiency and tolerance to moderate water deficit correlate in 33 poplar genotypes from a Populus deltoides x Populus trichocarpa F1 progeny.

    Science.gov (United States)

    Monclus, R; Villar, M; Barbaroux, C; Bastien, C; Fichot, R; Delmotte, F M; Delay, D; Petit, J-M; Bréchet, C; Dreyer, E; Brignolas, F

    2009-11-01

    Genotypic variability for productivity, water-use efficiency and leaf traits in 33 genotypes selected from an F1 progeny of Populus deltoides Bartr. ex Marsh x Populus trichocarpa L. was explored under optimal and moderate water-deficit conditions. Saplings of the 33 genotypes were grown in a two-plot open field at INRA Orléans (France) and coppiced every year. A moderate water deficit was induced during two successive years on one plot by withholding irrigation, while the second one remained irrigated (control). Stem biomass and leaf structure (e.g., specific leaf area and leaf area) were measured in 2004 and 2005 and functional leaf traits (e.g., carbon isotope discrimination, Delta) were measured only in 2004. Tolerance to water deficit was estimated at genotype level as the ability to limit losses in biomass production in water deficit versus control trees. Stem biomass, leaf structure and Delta displayed a significant genotypic variability whatever the irrigation regime. For all traits, genotype ranks remained stable across years for similar irrigation conditions. Carbon isotope discrimination scaled negatively with productivity and leaf nitrogen content in controls. The most productive genotypes were the least tolerant to moderate water deficit. No relationship was evidenced between Delta and the level of tolerance to water deficit. The relationships between traits evidenced in this collection of P. deltoides x P. trichocarpa F1 genotypes contrast with the ones that were previously detected in a collection of P. deltoides x Populus nigra L. cultivars tested in the same field trial.

  20. Can dendrochronology procedures estimate historical Tree Water Footprint?

    Science.gov (United States)

    Fernandes, Tarcísio J. G.; Del Campo, Antonio D.; Molina, Antonio J.

    2013-04-01

    Whole estimates of tree water use are becoming increasingly important in forest science and forest scientists have long sought to develop reliable techniques to estimate tree water use. In this sense accurately determining or estimate the quantity of water transpired by trees and forests is important and can be used to determine "green" water footprint. The use of dendrochronology is relative common in the study of effects and interactions between growth and climatic variables, but few studies deal with the relationship with water footprint. The main objective of this study is determining the historical tree water-use in a planted stand by dendrochronological approaches. This study was performed in South-eastern Spain, in an area covered by 50-60 years old Pinus halepensis Mil. plantations with high tree density (ca.1288/ha) due to low forest management. The experimental set-up consisted of two plots (30x30m), one corresponding to a thinning treatment performed in 2008 (t10) and the other thinned in 1998 (t1) to assess the mid-term effects of thinning. After one year of thinning four representative trees were select in each plot to measure transpiration by heat pulse sensor (sapflow velocity, vs). The accumulated daily values of transpiration (L day-1) were estimated multiplying the values of vs by sapwood area of each selected tree. After transpiration measurements two cores per tree were taken for establishing the tree-rings chronologies. The cores were prepared, their ring-width were measured and standardised in basal area increment index (BAI-i) following usual dendrochronological methods. The dendrochronology analyses showed a general variability in ring width during the initial growth (15 years), while in the following years the width rings were very small, conditioned by climate. The year after thinning (1999 or 2009) all trees in the treatments showed significant increases in ring width. The average vs for t1 and t10 were 3.59 cm h-1 and 1.95 cm h-1, and

  1. Extreme Water Deficit in Brazil Detected from Space

    Science.gov (United States)

    Vieira Getirana

    2016-01-01

    Extreme droughts have caused significant socioeconomic and environmental damage worldwide. In Brazil, ineffective energy development and water management policies have magnified the impacts of recent severe droughts, which include massive agricultural losses, water supply restrictions, and energy rationing. Spaceborne remote sensing data advance our understanding of the spatiotemporal variability of large-scale droughts and enhance the detection and monitoring of extreme water-related events. In this study, data derived from the Gravity Recovery and Climate Experiment (GRACE) mission are used to detect and quantify an extended major drought over eastern Brazil and provide estimates of impacted areas and region-specific water deficits. Two structural breakpoint detection methods were applied to time series of GRACE-based terrestrial water storage anomalies (TWSA), determining when two abrupt changes occurred. One, in particular, defines the beginning of the current drought. Using TWSA, a water loss rate of 26.1 cmyr21 over southeastern Brazil was detected from 2012 to 2015. Based on analysis of Global Land Data Assimilation System(GLDAS) outputs, the extreme drought is mostly related to lower-than-usual precipitation rates, resulting in high soil moisture depletion and lower-than-usual rates of evapotranspiration. A reduction of 2023 of precipitation over an extended period of 3 years is enough to raise serious water scarcity conditions in the country. Correlations between monthly time series of both grid-based TWSA and ground-based water storage measurements at 16 reservoirs located within southeastern Brazil varied from 0.42 to 0.82. Differences are mainly explained by reservoir sizes and proximity to the drought nucleus.

  2. Water-deficit tolerant classification in mutant lines of indica rice

    Directory of Open Access Journals (Sweden)

    Suriyan Cha-um

    2012-04-01

    Full Text Available Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control as water deficit sensitive, using Ward's method.

  3. PHYSIOLOGICAL RESPONSES OF DWARF COCONUT PLANTS UNDER WATER DEFICIT IN SALT - AFFECTED SOILS

    Directory of Open Access Journals (Sweden)

    ALEXANDRE REUBER ALMEIDA DA SILVA

    2017-01-01

    Full Text Available The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ̳Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity, acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index. The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m - 1 . Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.

  4. Deficiência hídrica, trocas gasosas e crescimento de raízes em laranjeira ‘Valência’ sobre dois tipos de porta-enxertos Water deficit, gas exchange and root growth in 'Valencia' orange tree budded on two rootstocks

    Directory of Open Access Journals (Sweden)

    José Rodrigues Magalhães Filho

    2008-01-01

    Full Text Available O crescimento e a distribuição do sistema radicular afetam as respostas das plantas à ocorrência de deficiência hídrica. Este trabalho teve como objetivo avaliar em mudas de laranjeira 'Valência' enxertada sobre limoeiro 'Cravo' ou Poncirus trifoliata ('Trifoliata' o crescimento de raízes, as trocas gasosas (CO2 e H2O, o potencial da água na folha e a distribuição de carboidratos nos diversos órgãos, em plantas submetidas à deficiência hídrica. As mudas foram transplantadas para 32 rizotrons, que permitiam a visualização das raízes, sendo 16 para cada porta-enxerto e submetidas ou não à irrigação. A deficiência hídrica às plantas foi aplicada pela interrupção do fornecimento de água às plantas. A condutância estomática decaiu após o quarto dia sem irrigação, causando redução da fotossíntese, da transpiração e da eficiência de carboxilação. O teor de carboidrato total (sacarose + açúcares redutores + amido em plantas sem estresse foi maior em 'Trifoliata', e entre os tratamentos com deficiência hídrica foi sempre inferior. As massas secas das plantas sem deficiência hídrica foram maiores, em ambos os porta-enxertos. Entre os tratamentos irrigados e não irrigados, o comprimento das raízes dentro de um mesmo tipo de porta-enxerto foram semelhantes. Porém, o comprimento das raízes de laranjeira 'Valência' sobre 'Cravo' foi significativamente maior. Mesmo sob deficiência hídrica e grande queda da produção fotossintética, as raízes permaneceram crescendo, possivelmente às expensas de substrato mobilizado de outros órgãos.The growth and distribution of the root system affect the response of the plants to water deficit. This work aim at the to evaluation of 'Valencia' orange budded on 'Rangpur¢ lime and Poncirus trifoliata ('Trifoliata' as to root growth, gas exchange (CO2 and H2O, leaf water potential and distribution of carbohydrates in several organs, in plants submitted to water deficit

  5. Medium term water deficit elicits distinct transcriptome responses in Eucalyptus species of contrasting environmental origin.

    Science.gov (United States)

    Spokevicius, Antanas V; Tibbits, Josquin; Rigault, Philippe; Nolin, Marc-Alexandre; Müller, Caroline; Merchant, Andrew

    2017-04-07

    Climatic and edaphic conditions over geological timescales have generated enormous diversity of adaptive traits and high speciation within the genus Eucalyptus (L. Hér.). Eucalypt species occur from high rainfall to semi-arid zones and from the tropics to latitudes as high as 43°S. Despite several morphological and metabolomic characterizations, little is known regarding gene expression differences that underpin differences in tolerance to environmental change. Using species of contrasting taxonomy, morphology and physiology (E. globulus and E. cladocalyx), this study combines physiological characterizations with 'second-generation' sequencing to identify key genes involved in eucalypt responses to medium-term water limitation. One hundred twenty Million high-quality HiSeq reads were created from 14 tissue samples in plants that had been successfully subjected to a water deficit treatment or a well-watered control. Alignment to the E. grandis genome saw 23,623 genes of which 468 exhibited differential expression (FDR < 0.01) in one or both ecotypes in response to the treatment. Further analysis identified 80 genes that demonstrated a significant species-specific response of which 74 were linked to the 'dry' species E. cladocalyx where 23 of these genes were uncharacterised. The majority (approximately 80%) of these differentially expressed genes, were expressed in stem tissue. Key genes that differentiated species responses were linked to photoprotection/redox balance, phytohormone/signalling, primary photosynthesis/cellular metabolism and secondary metabolism based on plant metabolic pathway network analysis. These results highlight a more definitive response to water deficit by a 'dry' climate eucalypt, particularly in stem tissue, identifying key pathways and associated genes that are responsible for the differences between 'wet' and 'dry' climate eucalypts. This knowledge provides the opportunity to further investigate and understand the mechanisms and

  6. Tree water status and growth of saplings and mature Norway spruce (Picea abies at a dry distribution limit

    Directory of Open Access Journals (Sweden)

    Walter eOberhuber

    2015-09-01

    Full Text Available We evaluated the size effect on stem water status and growth in Norway spruce (Picea abies (L. Karst. occurring at the edge of its natural range in a dry inner Alpine environment (750 m asl, Tyrol, Austria. Intra-annual dynamics of stem water deficit (ΔW, maximum daily shrinkage (MDS and radial growth (RG were compared among saplings (stem diameter/height: 2.2 cm/93 cm; n = 7 and mature adult trees (25 cm/12.7 m; n = 6 during 2014. ΔW, MDS and RG were extracted from stem diameter variations, which were continuously recorded by automatic dendrometers and the influence of environmental drivers was evaluated by applying moving correlation analysis (MCA. Additionally, we used Morlet wavelet analysis to assess the differences in cyclic radial stem variations between saplings and mature trees. Results indicate that saplings and mature trees were experiencing water limitation throughout the growing season. However, saplings exhibited a more strained stem water status and higher sensitivity to environmental conditions than mature trees. Hence, the significantly lower radial increments in saplings (0.16 ± 0.03 mm compared to mature trees (0.54 ± 0.14 mm is related to more constrained water status in the former, affecting the rate and duration of RG. The wavelet analysis consistently revealed more distinct diurnal stem variations in saplings compared to mature trees. Intra-annual RG was most closely related to climate variables that influence transpiration, i.e., vapor pressure deficit, relative air humidity, and air temperature. MCA, however, showed pronounced instability of climate-growth relationships, which masked missing temporal or significant correlations when the entire study period (April-October was considered. We conclude that an increase in evaporative demand will impair regeneration and long-term stability of drought-prone inner Alpine Norway spruce forests.

  7. High sensitivity of northeastern broadleaf forest trees to water availability

    Science.gov (United States)

    Levesque, M.; Pederson, N.; Andreu-Hayles, L.

    2015-12-01

    Temperate deciduous forests of eastern US provide goods and services to millions of people and play a vital role in the terrestrial carbon and hydrological cycles. However, ongoing climate change and increased in CO2 concentration in the atmosphere (ca) are expected to alter growth and gas exchange of trees, and ultimately forest productivity. Still, the magnitude of these effects is unclear. A better comprehension of the species-specific responses to environmental changes will better inform models and managers on the vulnerability and resiliency of these forests. Tree-ring analysis was combined with δ¹³C and δ18O measurements to investigate growth and physiological responses of red oak (Quercus rubra L.) and tulip poplar (Liriodendron tulipifera L.) in northeastern US to changes in water availability and ca for the period 1950-2014. We found very strong correlations between summer climatic water balance (June-August) and isotopic tree-ring series for δ¹³C (r = -0.65 and -0.73), and δ18O (r = -0.59 and -0.70), for red oak and tulip poplar, respectively. In contrast, tree-ring width was less sensitive to summer water availability (r = 0.33-0.39). Prior to the mid 1980s, low water availability resulted in low stomatal conductance, photosynthesis, and growth. Since that period, pluvial conditions occurring in northeastern US have increased stomatal conductance, carbon uptake, and growth of both species. These findings demonstrate that broadleaf trees in this region could be more sensitive to drought than expected. This appears especially true since much of the calibration period looks wet in a multi-centennial perspective. Further, stronger spatial correlations were found between climate data with tree-ring isotopes than with tree-ring width and the geographical area of the observed δ18O-precipitation response (i.e. the area over which correlations are > 0.5) covers most of the northeastern US. Given the good fit between the isotopic time series and water

  8. Dominant clonal Eucalyptus grandis x urophylla trees use water more efficiently

    Science.gov (United States)

    Marina Shinkai Gentil Otto; Robert M. Hubbard; Dan Binkley; Jose Luis Stape

    2014-01-01

    Wood growth in trees depends on the acquisition of resources, and can vary with tree size leading to a variety of stand dynamics. Typically, larger trees obtain more resources and grow faster than smaller trees, but while light has been addressed more often, few case studies have investigated the contributions of water use and water use efficiency (WUE) within stands...

  9. Impact of water-deficit stress on tritrophic interactions in a wheat-aphid-parasitoid system.

    Directory of Open Access Journals (Sweden)

    Syed Suhail Ahmed

    Full Text Available Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius, tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead. The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.

  10. Genetic control of plasticity in root morphology and anatomy of rice in response to water deficit

    NARCIS (Netherlands)

    Kadam, Niteen N.; Tamilselvan, Anandhan; Lawas, Lovely M.F.; Quinones, Cherryl; Bahuguna, Rajeev N.; Thomson, Michael J.; Dingkuhn, Michael; Muthurajan, Raveendran; Struik, Paul C.; Yin, Xinyou; Jagadish, Krishna S.V.

    2017-01-01

    Elucidating the genetic control of rooting behavior under water-deficit stress is essential to breed climate-robust rice (Oryza sativa) cultivars. Using a diverse panel of 274 indica genotypes grown under control and water-deficit conditions during vegetative growth, we phenotyped 35 traits, mostly

  11. Water-deficit inducible expression of a cytokinin biosynthetic gene IPT improves drought tolerance in cotton

    Science.gov (United States)

    Water-deficit stress is a major environmental factor that limits agricultural productivity worldwide. Recent episodes of extreme drought have severely affected cotton production in the Southwestern USA. There is a pressing need to develop cotton varieties with improved tolerance to water-deficit str...

  12. The watering of trees. Embolization and recovery in xylem microtubes

    CERN Document Server

    Gouin, Henri

    2014-01-01

    In any tree, crude sap is driven through xylem microtubes. The crude sap is submitted to intermolecular forces shaping it into very thin liquid films in embolized xylem microtubes. The concept of disjoining pressure must be taken into account and a strong negative pressure can be present in liquid-water bulks. The disjoining pressure gradient induced by the flux of transpiration initiates crude sap motion. Applications enable to understand why the xylem microtubes can be refilled and why the ascent of sap is possible even for the tallest trees avoiding the problems due to cavitation.

  13. Ectomycorrhizas and water relations of trees: a review.

    Science.gov (United States)

    Lehto, Tarja; Zwiazek, Janusz J

    2011-02-01

    There is plenty of evidence for improved nutrient acquisition by ectomycorrhizas in trees; however, their role in water uptake is much less clear. In addition to experiments showing improved performance during drought by mycorrhizal plants, there are several studies showing reduced root hydraulic conductivity and reduced water uptake in mycorrhizal roots. The clearest direct mechanism for increased water uptake is the increased extension growth and absorbing surface area, particularly in fungal species with external mycelium of the long-distance exploration type. Some studies have found increased aquaporin function and, consequently, increased root hydraulic conductivity in ectomycorrhizal plants while other studies showed no effect of ectomycorrhizal associations on root water flow properties. The aquaporin function of the fungal hyphae is also likely to be important for the uptake of water by the ectomycorrhizal plant, but more work needs to be done in this area. The best-known indirect mechanism for mycorrhizal effects on water relations is improved nutrient status of the host. Others include altered carbohydrate assimilation via stomatal function, possibly mediated by changes in growth regulator balance; increased sink strength in mycorrhizal roots; antioxidant metabolism; and changes in osmotic adjustment. None of these possibilities has been sufficiently explored. The mycorrhizal structure may also reduce water movement because of different fine root architecture (thickness), cell wall hydrophobicity or the larger number of membranes that water has to cross on the way from the soil to the xylem. In future studies, pot experiments comparing mycorrhizal and nonmycorrhizal plants will still be useful in studying well-defined physiological details. However, the quantitative importance of ectomycorrhizas for tree water uptake and water relations can only be assessed by field studies using innovative approaches. Hydraulic redistribution can support nutrient uptake

  14. Water deficit during pit hardening enhances phytoprostanes content, a plant biomarker of oxidative stress, in extra virgin olive oil.

    Science.gov (United States)

    Collado-González, Jacinta; Pérez-López, David; Memmi, Houssem; Gijón, M Carmen; Medina, Sonia; Durand, Thierry; Guy, Alexandre; Galano, Jean-Marie; Ferreres, Federico; Torrecillas, Arturo; Gil-Izquierdo, Angel

    2015-04-15

    No previous information exists on the effects of water deficit on the phytoprostanes (PhytoPs) content in extra virgin olive oil from fruits of mature olive (Olea europaea L. cv. Cornicabra) trees during pit hardening. PhytoPs profile in extra virgin olive oil was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 9-epi-9-D1t-PhytoP, 9-D1t-PhytoP, 16-B1-PhytoP + ent-16-B1-PhytoP, and 9-L1-PhytoP + ent-9-L1-PhytoP. The qualitative and quantitative differences in PhytoPs content with respect to those reported by other authors indicate a decisive effect of cultivar, oil extraction technology, and/or storage conditions prone to autoxidation. The pit hardening period was critical for extra virgin olive oil composition because water deficit enhanced the PhytoPs content, with the concomitant potential beneficial aspects on human health. From a physiological and agronomical point of view, 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, and 16-B1-PhytoP + ent-16-B1-PhytoP could be considered as early candidate biomarkers of water stress in olive tree.

  15. Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: source water versus needle water enrichment

    National Research Council Canada - National Science Library

    Treydte, Kerstin; Boda, Sonja; Graf Pannatier, Elisabeth; Fonti, Patrick; Frank, David; Ullrich, Bastian; Saurer, Matthias; Siegwolf, Rolf; Battipaglia, Giovanna; Werner, Willy; Gessler, Arthur

    2014-01-01

    ... to the tree rings of Larix decidua at two alpine sites in the Lötschental (Switzerland). Weekly resolved δ 18 O records of precipitation, soil water, xylem and needle water, phloem organic matter and tree rings were developed...

  16. Response of Maize to Nutrients Foliar Application Under Water Deficit Stress Conditions

    OpenAIRE

    N. A Sajedi; M.R. Ardakani; A Naderi; H Madani; M. M. A. Boojar

    2009-01-01

    Problem statement: To investigate the effect of nutrient application on agronomical characteristic and water use efficiency under water deficit stress of hybrid maize 704, an experiment was arranged in a split plot factorial based on a complete randomized block design with four replicates in the research station of Islamic Azad University-Arak Branch, Iran in 2007. Approach: Main factors studied were four irrigation levels including irrigation equal to crop water requirement, water deficit st...

  17. Microenvironment in the canopy rivals the host tree water status in controlling sap flow of a mistletoe species.

    Science.gov (United States)

    Yang, Da; Goldstein, Guillermo; Wang, Miao; Zhang, Wei-Wei; Wang, Ai-Ying; Liu, Yan-Yan; Hao, Guang-You

    2017-04-01

    Mistletoes absorb water from the vascular system of their hosts and thus the water use of mistletoes can be influenced by the water status of their hosts besides abiotic environmental conditions; however, there is a lack of studies on the dynamics of mistletoe water utilization in relation to both types of controlling factors. By building a canopy platform at 20 m above the ground, we monitored the dynamic changes of sap flow of Viscum coloratum (Kom.) Nakai (Loranthaceae) in combination with continuous measurements of microclimatic variables and volumetric water content (VWC) of its host tree branch xylem. We found that the host tree VWC exhibited substantial fluctuations during sunny days but lower VWC of the host did not negatively affect the sap flow of V. coloratum. Hourly and daily mean transpiration rates (Esap) of V. coloratum calculated from sap flow measurements showed strong positive correlations with photosynthetic photon flux density (PPFD) and vapor pressure deficit (VPD) measured in close vicinity to the point of mistletoe attachment. The mean Esap of V. coloratum was substantially higher than that of their host during clear days (4.55 ± 0.54 vs 2.01 ± 0.15 kg m-2 day-1). Moreover, the mistletoe-to-host transpiration ratio was not constant but became increasingly larger with the increase of PPFD or VPD on both hourly and daily bases, suggesting a weaker control of water loss in the mistletoe in comparison to its host species. The strong dependence of mistletoe Esap on micrometeorological variables and its decoupling from the host tree xylem water status suggests that the development of dense tree canopy functions as a potential mechanism for the host trees in reducing the competitive water use of mistletoes. These findings have important implications for the interactions between mistletoe species and their host trees in temperate forests. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email

  18. Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering

    Science.gov (United States)

    Penella, Consuelo; Calatayud, Ángeles; Melgar, Juan C.

    2017-01-01

    Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control) of two cultivars (‘Scarletprince’ and ‘CaroTiger’). Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO2 assimilation and stomatal conductance of water-stressed ‘Scarletprince’ trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed ‘Scarletprince’ trees was improved to values similar to control trees. On the other hand, water-stressed ‘CaroTiger’ trees needed two applications of ascorbic acid to reach values of CO2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with ‘Scarletprince’ trees preferentially using proline as compatible solute and ‘CaroTiger’ trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes. PMID:28979284

  19. Ascorbic Acid Alleviates Water Stress in Young Peach Trees and Improves Their Performance after Rewatering.

    Science.gov (United States)

    Penella, Consuelo; Calatayud, Ángeles; Melgar, Juan C

    2017-01-01

    Exogenous application of biochemicals has been found to improve water stress tolerance in herbaceous crops but there are limited studies on deciduous fruit trees. The goal of this research was to study if ascorbic acid applications could improve physiological mechanisms associated with water stress tolerance in young fruit trees. Ascorbic acid was foliarly applied at a concentration of 250 ppm to water-stressed and well-watered peach trees (control) of two cultivars ('Scarletprince' and 'CaroTiger'). Trees received either one or two applications, and 1 week after the second application all trees were rewatered to field capacity. Upon rewatering, CO 2 assimilation and stomatal conductance of water-stressed 'Scarletprince' trees sprayed with ascorbic acid (one or two applications) were similar to those of well-irrigated trees, but water-stressed trees that had not received ascorbic acid did not recover photosynthetical functions. Also, water status in sprayed water-stressed 'Scarletprince' trees was improved to values similar to control trees. On the other hand, water-stressed 'CaroTiger' trees needed two applications of ascorbic acid to reach values of CO 2 assimilation similar to control trees but these applications did not improve their water status. In general terms, different response mechanisms to cope with water stress in presence of ascorbic acid were found in each cultivar, with 'Scarletprince' trees preferentially using proline as compatible solute and 'CaroTiger' trees relying on stomatal regulation. The application of ascorbic acid reduced cell membrane damage and increased catalase activity in water-stressed trees of both cultivars. These results suggest that foliar applications of ascorbic acid could be used as a management practice for improving water stress tolerance of young trees under suboptimal water regimes.

  20. Osmosis at constant volume and water uptake in tall trees

    OpenAIRE

    Zupanovic, Pasko; Brumen, Milan; Fajmut, Ales; Kuic, Domagoj; Juretic, Davor

    2009-01-01

    We consider a thermodynamic state of a solvent and solution separated with an elastic semipermeable membrane in a box with a constant volume and the relevance of this simple model for the water uptake in tall trees. Under moderate concentrations of a solute, the solution and solvent are under the positive and negative pressure, respectively. In the case of the soft membrane the pressure difference between the compartments with the solvent and solution is given by van't Hoff equation. A state ...

  1. Use of thermal dissipation probes to estimate water loss of containerized landscape trees

    OpenAIRE

    Montague, Thayne; Kjelgren, Roger

    2006-01-01

    Granier style thermal dissipation probes (TDPs) have been used to estimate whole plant water use on a variety of tree and vine species. However, studies using TDPs and load cells (gravimetric water loss) to estimate water use of landscape tree species are rare. This research compared gravimetric water loss (extimated with load cells) of four containerized landscape tree species with water loss estimated with TDPs. Over a 66 day period, an experiment compared water loss of three established...

  2. Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest

    Science.gov (United States)

    Young, Jessica; Bolton, W. Robert; Bhatt, Uma; Cristobal, Jordi; Thoman, Richard

    2016-01-01

    The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21–25% of the available snowmelt water, while coniferous trees removed boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds.

  3. Effects of Nutrients Foliar Application on Agrophysiological Characteristics of Maize under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Nour Ali SAJEDI

    2010-09-01

    Full Text Available To investigate effects of nutrients foliar application on agrophysiological characteristics of maize hybrid �KSC 704� water deficit stress conditions, an experiment was arranged in a split plot factorial based on a randomized complete block design with four replications to the Research Station of Islamic Azad University-Arak Branch, Iran in 2007-2008. Main factors studied were four irrigation levels including irrigation equal to crop water requirement, water deficit stress at eight-leaf stage (V8, blister stage (R2 and filling grain stage (R4 in the main plot. Combined levels of selenium treatment (without and with application 20 gha-1 and micronutrients (without and with application 2 lha-1 were situated in sub plots. Results showed that water deficit stress decreased grain yield 19.7% in blister stage as compared with control. Using selenium increased relative content water at R2 and R4 stages significantly. Using selenium in water deficit stress condition increased measured traits except plant height as compared with treatment without selenium. A negative antagonistic interaction was found between selenium and micronutrients on some measured traits. Between treatments of water deficit stress, highest grain yield equal 6799.52 and 6736.97 kgha-1 was obtained from combined treatments of water deficit stress at eight-leaf stage+without selenium+without micronutrients and water deficit stress at eight-leaf stage+selenium+without micronutrients respectively which compared with treatment of irrigation equal to crop water requirement+selenium+microelements did not differ significant. According to the results of experiment, it is concluded that with micronutrients fertilizer spray under optimum irrigation and selenium spray under water deficit obtain optimum yield.

  4. Effects of Nutrients Foliar Application on Agrophysiological Characteristics of Maize under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Nour Ali SAJEDI

    2010-09-01

    Full Text Available To investigate effects of nutrients foliar application on agrophysiological characteristics of maize hybrid KSC 704 water deficit stress conditions, an experiment was arranged in a split plot factorial based on a randomized complete block design with four replications to the Research Station of Islamic Azad University-Arak Branch, Iran in 2007-2008. Main factors studied were four irrigation levels including irrigation equal to crop water requirement, water deficit stress at eight-leaf stage (V8, blister stage (R2 and filling grain stage (R4 in the main plot. Combined levels of selenium treatment (without and with application 20 gha-1 and micronutrients (without and with application 2 lha-1 were situated in sub plots. Results showed that water deficit stress decreased grain yield 19.7% in blister stage as compared with control. Using selenium increased relative content water at R2 and R4 stages significantly. Using selenium in water deficit stress condition increased measured traits except plant height as compared with treatment without selenium. A negative antagonistic interaction was found between selenium and micronutrients on some measured traits. Between treatments of water deficit stress, highest grain yield equal 6799.52 and 6736.97 kgha-1 was obtained from combined treatments of water deficit stress at eight-leaf stage+without selenium+without micronutrients and water deficit stress at eight-leaf stage+selenium+without micronutrients respectively which compared with treatment of irrigation equal to crop water requirement+selenium+microelements did not differ significant. According to the results of experiment, it is concluded that with micronutrients fertilizer spray under optimum irrigation and selenium spray under water deficit obtain optimum yield.

  5. Effects of Recent Minimum Temperature and Water Deficit Increases on Pinus pinaster Radial Growth and Wood Density in Southern Portugal.

    Science.gov (United States)

    Kurz-Besson, Cathy B; Lousada, José L; Gaspar, Maria J; Correia, Isabel E; David, Teresa S; Soares, Pedro M M; Cardoso, Rita M; Russo, Ana; Varino, Filipa; Mériaux, Catherine; Trigo, Ricardo M; Gouveia, Célia M

    2016-01-01

    Western Iberia has recently shown increasing frequency of drought conditions coupled with heatwave events, leading to exacerbated limiting climatic conditions for plant growth. It is not clear to what extent wood growth and density of agroforestry species have suffered from such changes or recent extreme climate events. To address this question, tree-ring width and density chronologies were built for a Pinus pinaster stand in southern Portugal and correlated with climate variables, including the minimum, mean and maximum temperatures and the number of cold days. Monthly and maximum daily precipitations were also analyzed as well as dry spells. The drought effect was assessed using the standardized precipitation-evapotranspiration (SPEI) multi-scalar drought index, between 1 to 24-months. The climate-growth/density relationships were evaluated for the period 1958-2011. We show that both wood radial growth and density highly benefit from the strong decay of cold days and the increase of minimum temperature. Yet the benefits are hindered by long-term water deficit, which results in different levels of impact on wood radial growth and density. Despite of the intensification of long-term water deficit, tree-ring width appears to benefit from the minimum temperature increase, whereas the effects of long-term droughts significantly prevail on tree-ring density. Our results further highlight the dependency of the species on deep water sources after the juvenile stage. The impact of climate changes on long-term droughts and their repercussion on the shallow groundwater table and P. pinaster's vulnerability are also discussed. This work provides relevant information for forest management in the semi-arid area of the Alentejo region of Portugal. It should ease the elaboration of mitigation strategies to assure P. pinaster's production capacity and quality in response to more arid conditions in the near future in the region.

  6. A GRACE-based water storage deficit approach for hydrological drought characterization

    Science.gov (United States)

    Thomas, Alys C.; Reager, John T.; Famiglietti, James S.; Rodell, Matthew

    2014-03-01

    We present a quantitative approach for measuring hydrological drought occurrence and severity based on terrestrial water storage observations from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission. GRACE measurements are applied by calculating the magnitude of the deviation of regional, monthly terrestrial water storage anomalies from the time series' monthly climatology, where negative deviations represent storage deficits. Monthly deficits explicitly quantify the volume of water required to return to normal water storage conditions. We combine storage deficits with event duration to calculate drought severity. Drought databases are referenced to identify meteorological drought events in the Amazon and Zambezi River basins and the southeastern United States and Texas regions. This storage deficit method clearly identifies hydrological drought onset, end, and duration; quantifies instantaneous severity and peak drought magnitude; and compares well with the meteorological drought databases. It also reveals information about the hydrological effects of meteorological drought on regional water storage.

  7. The nanofluidics can explain ascent of water in tallest trees

    CERN Document Server

    Gouin, Henri

    2012-01-01

    In Amazing numbers in biology, Flindt reports a giant, 128 meter-tall eucalyptus, and a 135 meter-tall sequoia. However, the explanation of the maximum altitude of the crude sap ascent and consequently the main reason of the maximum size that trees can reach is not well understood. According to tree species, the crude sap is driven in xylem microtubes with diameters ranging between 50 and 400 micrometers. The sap contains diluted salts but its physical properties are roughly those of water; consequently, hydrodynamic, capillarity and osmotic pressure yield a crude sap ascent of a few tens of meters only. Today, we can propound a new understanding of the ascent of sap to the top of very tall trees thanks to a new comparison between experiments associated with the cohesion-tension theory and the disjoining pressure concept. Here we show that the pressure in the water-storing tracheids of leaves can be strongly negative whereas the pressure in the xylem microtubes of stems may remain positive when, at high level...

  8. [Water use of re-vegetation pioneer tree species Schima superba and Acacia mangium in hilly land of South China].

    Science.gov (United States)

    Zhang, Zhen-Zhen; Zhao, Ping; Ni, Guang-Yan; Zhu, Li-Wei; Zhao, Xiu-Hua; Zhao, Pei-Qiang; Niu, Jun-Feng

    2014-04-01

    The xylem sap flows of two pioneer tree species, i.e., Acacia mangium and Schima superba, in degraded hill lands of South China, were continually monitored with Granier' s thermal dissipation probes during 2004-2007 and 2008-2012, respectively, and their seasonal transpiration changes at different tree age levels were compared. The results showed that the annual transpiration of both species increased with tree ages, and S. superba demonstrated a higher value than A. mangium. The average annual whole-tree transpiration of S. superba (7014.76 kg) was higher than that of A. mangium (3704.97 kg). A. mangium (511.46-1802.17 kg) had greater seasonal variation than S. superba (1346.48-2349.35 kg). The standard regression coefficients (beta) of transpiration (Eh), photosynthetically active radiation (PAR) and vapor pressure deficit (VPD) for both species increased with soil moisture, suggesting the increase of soil moisture generated a greater sensitivity of plants to environmental factors. Partial correlation analysis revealed that soil moisture played an important role in the seasonal variation of transpiration of both species. The optimum soil moistures of S. superba and A. mangium were 0.22-0.40 and 0.29-0.30 (V/V), respectively, indicating the native pioneer species S. superba better adapted to water deficit compared with exotic pioneer species A. mangium.

  9. Genes responding to water deficit in apple (Malus × domestica Borkh.) roots.

    Science.gov (United States)

    Bassett, Carole Leavel; Baldo, Angela M; Moore, Jacob T; Jenkins, Ryan M; Soffe, Doug S; Wisniewski, Michael E; Norelli, John L; Farrell, Robert E

    2014-07-08

    Individual plants adapt to their immediate environment using a combination of biochemical, morphological and life cycle strategies. Because woody plants are long-lived perennials, they cannot rely on annual life cycle strategies alone to survive abiotic stresses. In this study we used suppression subtractive hybridization to identify genes both up- and down-regulated in roots during water deficit treatment and recovery. In addition we followed the expression of select genes in the roots, leaves, bark and xylem of 'Royal Gala' apple subjected to a simulated drought and subsequent recovery. In agreement with studies from both herbaceous and woody plants, a number of common drought-responsive genes were identified, as well as a few not previously reported. Three genes were selected for more in depth analysis: a high affinity nitrate transporter (MdNRT2.4), a mitochondrial outer membrane translocase (MdTOM7.1), and a gene encoding an NPR1 homolog (MpNPR1-2). Quantitative expression of these genes in apple roots, bark and leaves was consistent with their roles in nutrition and defense. Additional genes from apple roots responding to drought were identified using suppression subtraction hybridization compared to a previous EST analysis from the same organ. Genes up- and down-regulated during drought recovery in roots were also identified. Elevated levels of a high affinity nitrate transporter were found in roots suggesting that nitrogen uptake shifted from low affinity transport due to the predicted reduction in nitrate concentration in drought-treated roots. Suppression of a NPR1 gene in leaves of drought-treated apple trees may explain in part the increased disease susceptibility of trees subjected to dehydrative conditions.

  10. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    Directory of Open Access Journals (Sweden)

    Hooz A Mendivelso

    Full Text Available A seasonal period of water deficit characterizes tropical dry forests (TDFs. There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

  11. Water stress strengthens mutualism among ants, trees, and scale insects.

    Science.gov (United States)

    Pringle, Elizabeth G; Akçay, Erol; Raab, Ted K; Dirzo, Rodolfo; Gordon, Deborah M

    2013-11-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  12. Water stress strengthens mutualism among ants, trees, and scale insects.

    Directory of Open Access Journals (Sweden)

    Elizabeth G Pringle

    2013-11-01

    Full Text Available Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  13. Transpiration and leaf growth of potato clones in response to soil water deficit

    Directory of Open Access Journals (Sweden)

    André Trevisan de Souza

    2014-04-01

    Full Text Available Potato (Solanum tuberosum ssp. Tuberosum crop is particularly susceptible to water deficit because of its small and shallow root system. The fraction of transpirable soil water (FTSW approach has been widely used in the evaluation of plant responses to water deficit in different crops. The FTSW 34 threshold (when stomatal closure starts is a trait of particular interest because it is an indicator of tolerance to water deficit. The FTSW threshold for decline in transpiration and leaf growth was evaluated in a drying soil to identify potato clones tolerant to water deficit. Two greenhouse experiments were carried out in pots, with three advanced clones and the cultivar Asterix. The FTSW, transpiration and leaf growth were measured on a daily basis, during the period of soil drying. FTSW was an efficient method to separate potato clones with regard to their response to water deficit. The advancedclones SMINIA 02106-11 and SMINIA 00017-6 are more tolerant to soil water deficit than the cultivar Asterix, and the clone SMINIA 793101-3 is more tolerant only under high solar radiation.

  14. Dynamics of transpiration, sap flow and use of stored water in tropical forest canopy trees.

    Science.gov (United States)

    Frederick C. Meinzer; Shelley A. James; Guillermo. Goldstein

    2004-01-01

    In large trees the daily onset of transpiration causes water to be withdrawn from internal storage compartments resulting in lags between changes in transpiration and sap flow at the base of the tree. We measured time courses of sap flow, hydraulic resistance, plant water potential and stomatal resistance in co-occuring tropical forest canopy trees with trunk diameters...

  15. Impacts of an invasive N2-fixing tree on Hawaiian stream water quality

    Science.gov (United States)

    Tracy N. Wiegner; Flint Hughes; Lisa M. Shizuma; David K. Bishaw; Mark E. Manuel

    2013-01-01

    N2-fixing trees can affect stream water quality. This has been documented in temperate streams, but not in tropical ones, even though N2-fixing trees are prevalent in the tropics. We investigated the effects of the introduced, invasive tree, Falcataria moluccanaalbiziaon water...

  16. Do ray cells provide a pathway for radial water movement in the stems of conifer trees?

    Science.gov (United States)

    David M. Barnard; Barbara Lachenbruch; Katherine A. McCulloh; Peter Kitin; Frederick C. Meinzer

    2013-01-01

    The pathway of radial water movement in tree stems presents an unknown with respect to whole-tree hydraulics. Radial profiles have shown substantial axial sap flow in deeper layers of sapwood (that may lack direct connection to transpiring leaves), which suggests the existence of a radial pathway for water movement. Rays in tree stems include ray tracheids and/or ray...

  17. Effects of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech

    Directory of Open Access Journals (Sweden)

    Fatih Bayraktar

    2015-04-01

    Full Text Available This study was designed to determine the effect of altitude on transpiration, leaf vapor pressure deficit and leaf water potential in oriental beech (Fagus orientalis Lipsky. The study area was located in Ortaköy, Artvin, and the experimental area had the same soil structure and aspect. The study showed that transpiration and leaf vapor pressure deficit increased but leaf water potential decreased by altitudinal gradient

  18. Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

    DEFF Research Database (Denmark)

    Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

    2016-01-01

    Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of ...... with increasing VPD and may necessitate revision of current models based on this assumption....

  19. Water deficit disrupts male gametophyte development in Quercus ilex.

    Science.gov (United States)

    Bykova, Olga; Limousin, Jean-Marc; Ourcival, Jean-Marc; Chuine, Isabelle

    2018-01-19

    Tree species distribution, and hence forest biodiversity, rely on the reproductive capacity of trees which is currently affected by climate change. Drought-induced pollen sterility could increase as a consequence of more intense and more frequent droughts projected for temperate and Mediterranean regions and threaten the sexual regeneration of trees in these regions. To evaluate this possibility, we examined the effect of long-term partial rainfall exclusion (-27% of precipitation) on male reproductive development in holm oak, Quercus ilex, one of the most important and widespread tree species of the Mediterranean region. We examined anther area, pollen production, pollen abortion as well as viable pollen production in control and dry treatments. Microscopic examinations revealed significant differences in pollen development between trees in the dry and the control treatments, even though anthesis occurred before the annual drought onset. Our results demonstrate that anthers collected from Q. ilex trees in the dry treatment, which experienced long-term increased drought stress especially during the summer time were the same size as anthers in the control treatment, but displayed 25% pollen abortion and almost 20% reduction in pollen production. Subsequently, the number of viable pollen grains in anthers from dry treatment was 35% less than in control. These results suggest a carry-over effect of drought stress on pollen production that could reduce the reproductive success of Q. ilex. The results of this study have broad implications for better understanding of the determinants of tree reproduction by masting and anticipate the outcomes of expected drought increase in the Mediterranean on forest dynamics. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Improving the water use efficiency of olive trees growing in water harvesting systems

    Science.gov (United States)

    Berliner, Pedro; Leake, Salomon; Carmi, Gennady; Agam, Nurit

    2017-04-01

    Water is a primary limiting factor for agricultural development in many arid and semi-arid regions in which a runoff generation is a rather frequent event. If conveyed to dyke surrounded plots and ponded, runoff water can thereafter be used for tree production. One of the most promising runoff collection configurations is that of micro-catchments in which water is collected close to the area in which runoff was generated and stored in adjacent shallow pits. The objective of this work was to assess the effect of the geometry of runoff water collection area (shallow pit or trench) on direct evaporative water losses and on the water use efficiency of olive trees grown in them. The study was conducted during the summer of 2013 and 2014. In this study regular micro-catchments with basins of 9 m2 (3 x 3 m) by 0.1 m deep were compared with trenches of one meter deep and one meter wide. Each configuration was replicated three times. One tree was planted in each shallow basin and the distance between trees in the 12 m long trench was four meters. Access tubes for neutron probes were installed in the micro-catchments and trenches (four and seven, respectively) to depths of 2.5 m. Soil water content in the soil profile was monitored periodically throughout drying periods in between simulated runoff events. Transpiration of the trees was estimated from half-hourly sap flow measurements using a Granier system. Total transpiration fluxes were computed for time intervals corresponding to consecutive soil water measurements. During the first year, a large runoff event was simulated by applying once four cubic meters to each plot; and in the second year the same volume of water was split into four applications, simulating a series of small runoff events. In both geometries, trees received the same amount of water per tree. Evaporation from trenches and micro-catchments was estimated as the difference between evapotranspiration obtained computing the differences in total soil water

  1. Water deficit affected flavonoid accumulation by regulating hormone metabolism in Scutellaria baicalensis Georgi roots.

    Directory of Open Access Journals (Sweden)

    Yuan Yuan

    Full Text Available The content of flavonoids especially baicalin and baicalein determined the medical quality of Scutellaria baicalensis which is a Chinese traditional medicinal plant. Here, we investigated the mechanism responsible for the content and composition of flavonoids in S. baicalensis under water deficit condition. The transcription levels of several genes which are involved in flavonoid biosynthesis were stimulated by water deficit. Under water deficit condition, fifteen up-regulated proteins, three down-regulated proteins and other six proteins were detected by proteomic analysis. The identified proteins include three gibberellin (GA- or indoleacetic acid (IAA-related proteins. Decreased endogenous GAs level and increased IAA level were observed in leaves of S. baicalensis which was treated with water deficit. Exogenous application of GA or α-naphthalene acelic acid (NAA to plants grown under water deficit conditions led to the increase of endogenous GAs and the decrease of IAA and flavonoids, respectively. When the synthesis pathway of GA or IAA in plants was inhibited by application with the inhibitors, flavonoid levels were recovered. These results indicate that water deficit affected flavonoid accumulation might through regulating hormone metabolism in S. baicalensis Georgi.

  2. Transcriptome changes in the cambial region of poplar (Populus alba L.) in response to water deficit.

    Science.gov (United States)

    Berta, M; Giovannelli, A; Sebastiani, F; Camussi, A; Racchi, M L

    2010-03-01

    A transcriptome analysis of the Populus alba cambial region was performed with the aim of elucidating the gene network underlying the response to water deficit within the cambium and differentiating derivative cambial cells. Water stress was induced in 1-year-old P. alba plants by withholding water for 9 days. At that time, leaf predawn water potential fell to -0.8 MPa, resulting in a significant reduction in stomatal conductance, CO(2) assimilation and a consistent increment of stem shrinkage. These effects were almost fully reversed by re-hydration. The water deficit resulted in changes in gene expression that affected several functional categories, such as protein metabolism, cell wall metabolism, stress response, transporters and transcriptional regulation. The function of up- and down-regulated genes is discussed considering the physiological response of the plants to water deficit.

  3. Late season sugarcane performance as affected by soil water deficit ...

    African Journals Online (AJOL)

    A field trial was carried out in Ferké 2 Sugar mill located in northern Ivory Coast, in order to study sugarcane growth and yield response to deficit irrigation imposed over the yield formation stage. The crop used was a first ratoon Co 957, a non flowering late season sugarcane variety. The experiment was completely ...

  4. Early daily trunk shrinkage is highly sensitive to water stress in nectarine trees

    Science.gov (United States)

    Pérez-Pastor, Alejandro; De la Rosa, Jose M.; Dodd, Ian C.; Conesa, María R.; Domingo, Rafael

    2014-05-01

    The sensitivity to water stress of different plant water status indicators was evaluated during two consecutive years in early nectarine trees grown in a semi-arid region. Measurements were made post-harvest and two irrigation treatments were applied: a control treatment (CTL), irrigated at 120% of crop evapotranspiration demand to achieve non-limiting water conditions, and a deficit irrigation treatment (DI), that applied around 37% less water than CTL during late postharvest. The plant water status indicators evaluated were midday stem water potential (Ψstem) and parameters derived from trunk diameter fluctuations (TDF): maximum daily shrinkage (MDS), trunk daily growth rate (TGR), early daily shrinkage measured between 0900 and 1200 h solar time (EDS), and late daily shrinkage (LDS) that occurred between 1200 h solar time and the moment that minimum trunk diameter was reached (typically 1600 h solar time). The most sensitive (highest ratio of signal intensity (SI) to noise) indicators to water stress were Ψstem together with EDS. The SI of EDS was greater than that of Ψstem, although with greater variability. EDS was a better indicator than MDS, with higher SI and similar variability. Although MDS was linearly related to Ψstem down to -1.5 MPa, thereafter MDS decreased with increasing water stress. In contrast, EDS was linearly related to Ψstem, although the slope of the regression decreased as the season progressed, as in the case of MDS. Further studies are needed to determine whether EDS is a sensitive indicator of water stress in a range of species.

  5. Effects of water stress on irradiance acclimation of leaf traits in almond trees.

    Science.gov (United States)

    Egea, Gregorio; González-Real, María M; Baille, Alain; Nortes, Pedro A; Conesa, María R; Ruiz-Salleres, Isabel

    2012-04-01

    Photosynthetic acclimation to highly variable local irradiance within the tree crown plays a primary role in determining tree carbon uptake. This study explores the plasticity of leaf structural and physiological traits in response to the interactive effects of ontogeny, water stress and irradiance in adult almond trees that have been subjected to three water regimes (full irrigation, deficit irrigation and rain-fed) for a 3-year period (2006-08) in a semiarid climate. Leaf structural (dry mass per unit area, N and chlorophyll content) and photosynthetic (maximum net CO(2) assimilation, A(max), maximum stomatal conductance, g(s,max), and mesophyll conductance, g(m)) traits and stem-to-leaf hydraulic conductance (K(s-l)) were determined throughout the 2008 growing season in leaves of outer south-facing (S-leaves) and inner northwest-facing (NW-leaves) shoots. Leaf plasticity was quantified by means of an exposure adjustment coefficient (ε=1-X(NW)/X(S)) for each trait (X) of S- and NW-leaves. Photosynthetic traits and K(s-l) exhibited higher irradiance-elicited plasticity (higher ε) than structural traits in all treatments, with the highest and lowest plasticity being observed in the fully irrigated and rain-fed trees, respectively. Our results suggest that water stress modulates the irradiance-elicited plasticity of almond leaves through changes in crown architecture. Such changes lead to a more even distribution of within-crown irradiance, and hence of the photosynthetic capacity, as water stress intensifies. Ontogeny drove seasonal changes only in the ε of area- and mass-based N content and mass-based chlorophyll content, while no leaf age-dependent effect was observed on ε as regards the physiological traits. Our results also indicate that the irradiance-elicited plasticity of A(max) is mainly driven by changes in leaf dry mass per unit area, in g(m) and, most likely, in the partitioning of the leaf N content.

  6. REPEATED MEASURES ANALYSIS OF CHANGES IN PHOTOSYNTHETIC EFFICIENCY IN SOUR CHERRY DURING WATER DEFICIT

    Directory of Open Access Journals (Sweden)

    Marija Viljevac

    2012-06-01

    Full Text Available The objective of this study was to investigate changes in photosynthetic efficiency applying repeated measures ANOVA using the photosynthetic performance index (PIABS of the JIP-test as a vitality parameter in seven genotypes of sour cherry (Prunus cerasus, L. during 10 days of continuous water deficit. Both univariate and multivariate ANOVA repeated measures revealed highly significant time effect (Days and its subsequent interactions with genotype and water deficit. However, the multivariate Pillai’s trace test detected the interaction Time × Genotype × Water deficit as not significant. According to the Tukey’s Studentized Range (HSD test, differences between the control and genotypes exposed to water stress became significant on the fourth day of the experiment, indicating that the plants on the average, began to lose their photosynthetic efficiency four days after being exposed to water shortage. It corroborates previous findings in other species that PIABS is very sensitive tool for detecting drought stress.

  7. Physiological parameters to select upland rice genotypes for tolerance to water deficit

    Directory of Open Access Journals (Sweden)

    Cleber Morais Guimarães

    2015-07-01

    Full Text Available Abstract: The objective of this work was to evaluate the feasibility of using physiological parameters for water deficit tolerance, as an auxiliary method for selection of upland rice genotypes. Two experiments - with or without water deficit - were carried out in Porangatu, in the state of Goiás, Brazil; the water deficit experiment received about half of irrigation that was applied to the well-watered experiment. Four genotypes with different tolerance levels to water stress were evaluated. The UPLRI 7, B6144F-MR-6-0-0, and IR80312-6-B-3-2-B genotypes, under water stress conditions, during the day, showed lower stomatal diffusive resistance, higher leaf water potential, and lower leaf temperature than the control. These genotypes showed the highest grain yields under water stress conditions, which were 534, 601, and 636 kg ha-1, respectively, and did not differ significantly among them. They also showed lower drought susceptibility index than the other genotypes. 'BRS Soberana' (susceptible control was totally unproductive under drought conditions. Leaf temperature is a easy-read parameter correlated to plant-water status, viable for selecting rice genotypes for water deficit tolerance.

  8. RNA-Seq reveals genotype-specific molecular responses to water deficit in eucalyptus.

    Science.gov (United States)

    Villar, Emilie; Klopp, Christophe; Noirot, Céline; Novaes, Evandro; Kirst, Matias; Plomion, Christophe; Gion, Jean-Marc

    2011-11-02

    In a context of climate change, phenotypic plasticity provides long-lived species, such as trees, with the means to adapt to environmental variations occurring within a single generation. In eucalyptus plantations, water availability is a key factor limiting productivity. However, the molecular mechanisms underlying the adaptation of eucalyptus to water shortage remain unclear. In this study, we compared the molecular responses of two commercial eucalyptus hybrids during the dry season. Both hybrids differ in productivity when grown under water deficit. Pyrosequencing of RNA extracted from shoot apices provided extensive transcriptome coverage - a catalog of 129,993 unigenes (49,748 contigs and 80,245 singletons) was generated from 398 million base pairs, or 1.14 million reads. The pyrosequencing data enriched considerably existing Eucalyptus EST collections, adding 36,985 unigenes not previously represented. Digital analysis of read abundance in 14,460 contigs identified 1,280 that were differentially expressed between the two genotypes, 155 contigs showing differential expression between treatments (irrigated vs. non irrigated conditions during the dry season), and 274 contigs with significant genotype-by-treatment interaction. The more productive genotype displayed a larger set of genes responding to water stress. Moreover, stress signal transduction seemed to involve different pathways in the two genotypes, suggesting that water shortage induces distinct cellular stress cascades. Similarly, the response of functional proteins also varied widely between genotypes: the most productive genotype decreased expression of genes related to photosystem, transport and secondary metabolism, whereas genes related to primary metabolism and cell organisation were over-expressed. For the most productive genotype, the ability to express a broader set of genes in response to water availability appears to be a key characteristic in the maintenance of biomass growth during the

  9. Does morphological and anatomical plasticity during the vegetative stage make wheat more tolerant of water deficit stress than rice?

    NARCIS (Netherlands)

    Kadam, N.N.; Yin, X.; Bindraban, P.S.; Struik, P.C.; Jagadish, K.S.V.

    2015-01-01

    Water scarcity and the increasing severity of water deficit stress are major challenges to sustaining irrigated rice (Oryza sativa) production. Despite the technologies developed to reduce the water requirement, rice growth is seriously constrained under water deficit stress compared with other

  10. Using FAO-56 model to estimate soil and crop water status: Application to a citrus orchard under regulated deficit irrigation

    Science.gov (United States)

    Provenzano, Giuseppe; Gonzàles-Altozano, Pablo; Manzano-Juàrez, Juan; Rallo, Giovanni

    2015-04-01

    Agro-hydrological models allow schematizing exchange processes in the soil-plant-atmosphere continuum (SPAC) on a wide range of spatial and temporal scales. Each section of the SPAC system is characterized by complex behaviours arising, for instance, the adaptive plant strategies in response to soil water deficit conditions. Regulated deficit irrigation (RDI) has been considered as one of the potential strategies for sustainable crop production in regions characterized by water scarcity. Moreover, reducing water supply at certain growth stages can improve water use efficiency (WUE) and quality of productions, without affecting significantly crop yield. Environmental policy requires to improve WUE in crops with high water requirements, so that it is necessary to identify easy-to-use tools aimed at irrigation water saving strategies, without the need of tedious and time consuming experiments. Accurate evaluation of crop water status and actual transpiration plays a key role in irrigation scheduling under RDI, in order to avoid that water stress becomes too severe and detrimental to yield and fruit quality. Objective of the research was to assess the suitability of FAO56 agro-hydrological model (Allen et al., 1998) on citrus orchards under different water deficit conditions, to estimate soil and crop water status. The ability of the model to predict actual crop water stress was evaluated based on the temporal dynamic of simulated relative transpirations and on the similarities with the corresponding dynamic of measured midday stem water potentials, MSWP. During dry periods, simulated relative crop transpiration was correlated to MSWP with the aim to assess the model ability to predict crop water stress and to identify "plant-based" irrigation scheduling parameters. Experiments were carried out during three years from 2009 and 2011 in Senyera (39° 3' 35.4" N, 0° 30' 28.2" W), Spain, in a commercial orchard planted with Navelina/Cleopatra citrus trees. Three RDI

  11. [Spectrum Variance Analysis of Tree Leaves Under the Condition of Different Leaf water Content].

    Science.gov (United States)

    Wu, Jian; Chen, Tai-sheng; Pan, Li-xin

    2015-07-01

    Leaf water content is an important factor affecting tree spectral characteristics. So Exploring the leaf spectral characteristics change rule of the same tree under the condition of different leaf water content and the spectral differences of different tree leaves under the condition of the same leaf water content are not only the keys of hyperspectral vegetation remote sensing information identification but also the theoretical support of research on vegetation spectrum change as the differences in leaf water content. The spectrometer was used to observe six species of tree leaves, and the reflectivity and first order differential spectrum of different leaf water content were obtained. Then, the spectral characteristics of each tree species leaves under the condition of different leaf water content were analyzed, and the spectral differences of different tree species leaves under the condition of the same leaf water content were compared to explore possible bands of the leaf water content identification by hyperspectral remote sensing. Results show that the spectra of each tree leaf have changed a lot with the change of the leaf water content, but the change laws are different. Leaf spectral of different tree species has lager differences in some wavelength range under the condition of same leaf water content, and it provides some possibility for high precision identification of tree species.

  12. Future of Alpine Water Resources : Uncertainty from Trees and Glaciers

    Science.gov (United States)

    Ceperley, N. C.; Beria, H.; Michelon, A.; Schaefli, B.

    2016-12-01

    Alpine water resources are particularly susceptible to climate change, which presents a high risk to many of the ecologic and economic roles played by mountain environments. In Switzerland, water from glacier-fed catchments provides a large portion of hydroelectric power and water supply as well as a multitude of services including the creation and maintenance of biological communities and the physical landscape. Loss of glaciers will also pose indirect consequences, such as changing the hydrologic, biologic, and physical environment, for example opening up new surfaces for vegetation growth and forestation. Hydrologic models are a primary tool to predict these consequences. Quantifying evaporation is an on-going challenge for modeling, and changes in the partition between transpiration and evaporation from bare ground or sublimation from glaciers is a larve source of uncertainty in the alpine water balance. We just began an intensive monitoring program of hydrological processes in the Vallon de Nant, Switzerland (area of 14 km², altitude ranging from 1200 to 3051 m). This site is both a karst system and a protected area, making it a particularly interesting site to study eco-hydrologic processes. Monitoring of stable isotopes (δO18 and δD) in water combines with measurements of climate and hydrologic parameters to quantify flows through the components of the water balance and assess their certainty. Additionally, we are observing water use by trees at the upper limit of their habitat range. Our presentation will highlight the importance of in situ measurements to quantify the spatial and temporal variations in the water balance. We will discuss the innovative measurement techniques that we are deploying, the uncertainty from each component, and show the first results of our work.

  13. Recurrent water deficit causes epigenetic and hormonal changes in citrus plants.

    Science.gov (United States)

    Neves, Diana Matos; Almeida, Lucas Aragão da Hora; Santana-Vieira, Dayse Drielly Souza; Freschi, Luciano; Ferreira, Claudia Fortes; Soares Filho, Walter Dos Santos; Costa, Marcio Gilberto Cardoso; Micheli, Fabienne; Coelho Filho, Maurício Antônio; Gesteira, Abelmon da Silva

    2017-10-20

    The present study evaluated the physiological, molecular and hormonal parameters from scion/rootstock interaction of citrus plants during recurrent water deficit. Responses of the Valencia (VO) scion variety grafted on two rootstocks with different soil water extraction capacities, Rangpur Lime (RL) and Sunki Maravilha (SM), during three successive periods of water deficit: plants exposed to a single episode of water deficit (WD1) and plants exposed to two (WD2) and three (WD3) recurrent periods of WD were compared. The combinations VO/RL and VO/SM presented polymorphic alterations of epigenetic marks and hormonal (i.e. abscisic acid, auxins and salicylicacid) profiles, which were particularly prominent when VO/SM plantswere exposed toWD3 treatment. Upon successive drought events, the VO/SM combination presented acclimatization characteristics that enable higher tolerance to water deficit by increasing transpiration (E), stomatal conductance (g s ) and photosynthetic rate (A), which in turn may have facilitated the whole plant survival. Besides providing comprehensive data on the scion/rootstock interactions upon successive stress events, this study brings the first dataset suggesting that epigenetic alterations in citrus plants triggered by recurrent water deficit lead to improved drought tolerance in this crop species.

  14. Water-deficit inducible expression of a cytokinin biosynthetic gene IPT improves drought tolerance in cotton.

    Directory of Open Access Journals (Sweden)

    Sundaram Kuppu

    Full Text Available Water-deficit stress is a major environmental factor that limits agricultural productivity worldwide. Recent episodes of extreme drought have severely affected cotton production in the Southwestern USA. There is a pressing need to develop cotton varieties with improved tolerance to water-deficit stress for sustainable production in water-limited regions. One approach to engineer drought tolerance is by delaying drought-induced senescence via up-regulation of cytokinin biosynthesis. The isopentenyltransferase gene (IPT that encodes a rate limiting enzyme in cytokinin biosynthesis, under the control of a water-deficit responsive and maturation specific promoter P(SARK was introduced into cotton and the performance of the P(SARK::IPT transgenic cotton plants was analyzed in the greenhouse and growth chamber conditions. The data indicate that P(SARK::IPT-transgenic cotton plants displayed delayed senescence under water deficit conditions in the greenhouse. These plants produced more root and shoot biomass, dropped fewer flowers, maintained higher chlorophyll content, and higher photosynthetic rates under reduced irrigation conditions in comparison to wild-type and segregated non-transgenic lines. Furthermore, P(SARK::IPT-transgenic cotton plants grown in growth chamber condition also displayed greater drought tolerance. These results indicate that water-deficit induced expression of an isopentenyltransferase gene in cotton could significantly improve drought tolerance.

  15. Working to reverse a water deficit | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Fayez Bataineh's desire to become a water engineer began when he was a young boy. "Even at a young age I saw the people suffering from a lack of water," he recalls. "I was sometimes obligated to go to the city to bring back water for my family. So I was always dreaming about water." SEE ALSO...

  16. The influence of savanna trees on nutrient, water and light availability and the understorey vegetation

    NARCIS (Netherlands)

    Ludwig, F.; Kroon, de H.; Berendse, F.; Prins, H.H.T.

    2004-01-01

    In an East African savanna herbaceous layer productivity and species composition were studied around Acacia tortilis trees of three different age classes, as well as around dead trees and in open grassland patches. The effects of trees on nutrient, light and water availability were measured to

  17. Agronomical effects of deficit irrigation in apricot, peach and plum trees

    NARCIS (Netherlands)

    Torrecillas, Arturo; Corell, M.; Galindo Egea, Alejandro; Pérez-López, David; Memmi, Houssem; Rodriguez, Pedro; Cruz, Zulma N.; Centeno, Ana; Intrigliolo, Diego S.; Moriana, A.; Garcia Tejero, Ivan Francisco; Duran Zuazo, Victor Hugo

    2017-01-01

    Stone fruits are some of the most important irrigated crops around the world. Their ability to grow in different environments implies great variations in water needs. This chapter discusses the effect of water restriction on yield and quality of the fruits obtained. The information will provide

  18. Water deficit stress effects on corn (Zea mays, L.) root: shoot ratio

    Science.gov (United States)

    A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation...

  19. Policy tree optimization for adaptive management of water resources systems

    Science.gov (United States)

    Herman, Jonathan; Giuliani, Matteo

    2017-04-01

    Water resources systems must cope with irreducible uncertainty in supply and demand, requiring policy alternatives capable of adapting to a range of possible future scenarios. Recent studies have developed adaptive policies based on "signposts" or "tipping points" that suggest the need of updating the policy. However, there remains a need for a general method to optimize the choice of the signposts to be used and their threshold values. This work contributes a general framework and computational algorithm to design adaptive policies as a tree structure (i.e., a hierarchical set of logical rules) using a simulation-optimization approach based on genetic programming. Given a set of feature variables (e.g., reservoir level, inflow observations, inflow forecasts), the resulting policy defines both the optimal reservoir operations and the conditions under which such operations should be triggered. We demonstrate the approach using Folsom Reservoir (California) as a case study, in which operating policies must balance the risk of both floods and droughts. Numerical results show that the tree-based policies outperform the ones designed via Dynamic Programming. In addition, they display good adaptive capacity to the changing climate, successfully adapting the reservoir operations across a large set of uncertain climate scenarios.

  20. Trees

    Science.gov (United States)

    Al-Khaja, Nawal

    2007-01-01

    This is a thematic lesson plan for young learners about palm trees and the importance of taking care of them. The two part lesson teaches listening, reading and speaking skills. The lesson includes parts of a tree; the modal auxiliary, can; dialogues and a role play activity.

  1. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

    Science.gov (United States)

    Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

    2014-08-01

    Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. © 2014 John Wiley & Sons Ltd.

  2. Effect of water deficit stress on yield, physiological and biochemical parameters of two Iranian cantaloupe accessions

    Directory of Open Access Journals (Sweden)

    Hadi Lotfi

    2016-06-01

    Full Text Available Water deficit stress is one of the most important environmental factors limitting plant growth and crop production. In order to evaluate the tolerance of two Iranian melons to water deficit stress, an experiment in research filed of University of Zanjan was conducted. Treatments consisted of three Irrigation levels, starting irrigation at (100, 66 and 33 % Crop Evapotranspiration and two accessions of Iranian cantaloupes (Tile-Zard and Tile-Sabz. In this experiment, total chlorophyll content, carotenoids, proline content, leaf relative water content (RWC, ascorbic acid, peroxidase and catalase activity, yield and water use efficiency (WUE were evaluated. The results indicated that water deficit stress significantly increased proline content, peroxidase and catalase activity and WUE, but decreased RWC, yield and total chlorophyll content. The highest increase in proline content (34.8 %, catalase (18 % and proxidase (42.3 % activity and reduction in yield (61.6 % and RWC (8 % was obtained in 33 % ETc Irrigation. There has been significant difference between accesesions in relation to RWC, proline, total chlorophyll and peroxidase and catalase activity. The highest value of yield and WUE was observed in 'Tile-Zard'. According to the interaction results, both accessions, 'Tile-Sabz' and 'Tile-Zard' with 63.6 % and 59.7 % Reduction in fruit yield under deficit water stress, are.

  3. Do centennial tree-ring and stable isotope trends of Larix gmelinii (Rupr.) Rupr. indicate increasing water shortage in the Siberian north?

    Science.gov (United States)

    Sidorova, Olga Vladimirovna; Siegwolf, Rolf T W; Saurer, Matthias; Shashkin, Alexander V; Knorre, Anastasia A; Prokushkin, Anatoliy S; Vaganov, Eugene A; Kirdyanov, Alexander V

    2009-10-01

    Tree-ring width of Larix gmelinii (Rupr.) Rupr., ratios of stable isotopes of C (delta(13)C) and O (delta(18)O) of whole wood and cellulose chronologies were obtained for the northern part of central Siberia (Tura, Russia) for the period 1864-2006. A strong decrease in the isotope ratios of O and C (after atmospheric delta(13)C corrections) and tree-ring width was observed for the period 1967-2005, while weather station data show a decrease in July precipitation, along with increasing July air temperature and vapor pressure deficit (VPD). Temperature at the end of May and the whole month of June mainly determines tree radial growth and marks the beginning of the vegetation period in this region. A positive correlation between tree-ring width and July precipitation was found for the calibration period 1929-2005. Positive significant correlations between C isotope chronologies and temperatures of June and July were found for whole wood and cellulose and negative relationships with July precipitation. These relationships are strengthened when the likely physiological response of trees to increased CO(2) is taken into account (by applying a recently developed delta(13)C correction). For the O isotope ratios, positive relationships with annual temperature, VPD of July and a negative correlation with annual precipitation were observed. The delta(18)O in tree rings may reflect annual rather than summer temperatures, due to the late melting of the winter snow and its contribution to the tree water supply in summer. We observed a clear change in the isotope and climate trends after the 1960s, resulting in a drastic change in the relationship between C and O isotope ratios from a negative to a positive correlation. According to isotope fractionation models, this indicates reduced stomatal conductance at a relatively constant photosynthetic rate, as a response of trees to water deficit for the last half century in this permafrost region.

  4. Response of Jatropha curcas L. to water deficit: Yield, water use efficiency and oilseed characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Abou Kheira, Abdrabbo A. [Water Management Research Institute, National Water Research Center, Delta Barrage, P.O. Box 13621/5 (Egypt); Atta, Nahed M.M. [Oil and Fat Research Department, Food Technology Research Institute, Agricultural Research Center, Giza (Egypt)

    2009-10-15

    Field experiment was carried out at Enshas Experiment Station; Jatropha was transplanted and treated after the second year of the transplanting by different amounts of water stress, viz. 125%, 100%, 75% and 50% of potential evapotranspiration (ETp). The study aims to ensure the multiple benefits of Jatropha and its suitability under Egypt's climate in unused lands under scarce water conditions. The results revealed that the average water consumption rate of Jatropha is 6 L week{sup -1} throughout the growing season, which means that Jatropha can survive and produce full yield with high quality seeds under minimum water requirements compared to other crops. The yield of extracted oil was 85.5, 175.2, 90.5 and 66.5 kg ha{sup -1} at 125%, 100%, 75% and 50% of ETp, respectively. The lowest values of total lipid (oil) (25% and 24.5% of Jatropha seeds) were recorded with Jatropha trees that were irrigated by 125% and 50% of ETp, respectively. On the other hand, the treatment that was irrigated by 100% of ETp (control) recorded the highest value of total oil in the seeds (29.93%). The results also revealed that there are no significant differences among the values of the determined oil characteristics due to different water stress ratios. From the results, it could be concluded that the highest characteristics of Jatropha seed oil were recorded with 100% of ETp. In addition water stress had no significant effect on the fatty acid composition of Jatropha seed oil. (author)

  5. Functional magnetic resonance microscopy of long- and short-distance water transport in trees

    NARCIS (Netherlands)

    Homan, N.

    2009-01-01

    Due to their long life span, changing climatic conditions are of particular importance for trees. Climate changes will affect the water balance, which can become an important limiting factor for photosynthesis and growth. Long-distance water transport in trees is directly related to the

  6. Laboratory Results from Dielectric Spectroscopy of Field Aged XLPE Cables with Respect to Water Trees

    DEFF Research Database (Denmark)

    Pedersen, Kenneth; Sedding, Howard; Fenger, Mark

    2006-01-01

    This paper deals with the application of frequency domain dielectric spectroscopy for the detection of water trees in XLPE cables. During the research, dielectric spectroscopy measurements have been carried out on cable samples with and without water trees while it was attempted to preserve many ...

  7. How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment

    NARCIS (Netherlands)

    Limpens, J.; Holmgren, M.; Jacobs, C.M.J.; Zee, van der S.E.A.T.M.; Karofeld, E.; Berendse, F.

    2014-01-01

    Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree

  8. Sources of water used by trees and millet in Sahelian windbreak systems

    Science.gov (United States)

    Smith, D. Mark; Jarvis, Paul G.; Odongo, Julius C. W.

    1997-11-01

    The extent to which water use by trees and crops is complementary in agroforestry systems may be affected by the proximity of groundwater to the soil surface. This may have important implications for the planning and management of agroforestry in semi-arid regions such as the Sahel of West Africa. A method of distinguishing uptake of water by plants from different sources was used, therefore, at locations with contrasting water table levels, to determine whether Azadirachta indica A. Juss (neem) trees in windbreaks utilised water from the same depths as adjacent crops of pearl millet ( Pennisetum glaucum (L.) R. Br.). Comparisons of ratios of the stable isotopes of oxygen ( 18O/ 16O) in plant sap, groundwater and water in the unsaturated zone of the soil profile were made in the Majjia Valley, in south-central Niger, where groundwater was found at depths of 6-8 m, and at Sadoré in south-western Niger, where the water table was at a depth of 35 m. In the Majjia Valley, the trees obtained large portions of their water from surface layers of the soil only after rain, when water there was abundant. During dry periods, roots of the trees extracted groundwater or deep reserves of soil water, while the millet crop extracted water from closer to the top of the soil profile. In contrast, at Sadoré, both the trees and crop fulfilled their water requirements from the top 2-3 m of the soil throughout the year. Thus, utilisation of water by windbreak trees and crops is more complementary where groundwater is accessible to tree roots. Competition for water is likely reduced at such locations as a consequence, but may affect the productivity of windbreak systems where groundwater is inaccessible. To maximise the benefits of establishing windbreaks, therefore, it is important that planners recommend strategies for reducing competition for water between trees and crops at sites where groundwater cannot be reached by tree roots.

  9. The photosynthetic response of tobacco plants overexpressing ice plant aquaporin McMIPB to a soil water deficit and high vapor pressure deficit.

    Science.gov (United States)

    Kawase, Miki; Hanba, Yuko T; Katsuhara, Maki

    2013-07-01

    We investigated the photosynthetic capacity and plant growth of tobacco plants overexpressing ice plant (Mesembryanthemum crystallinum L.) aquaporin McMIPB under (1) a well-watered growth condition, (2) a well-watered and temporal higher vapor pressure deficit (VPD) condition, and (3) a soil water deficit growth condition to investigate the effect of McMIPB on photosynthetic responses under moderate soil and atmospheric humidity and water deficit conditions. Transgenic plants showed a significantly higher photosynthesis rate (by 48 %), higher mesophyll conductance (by 52 %), and enhanced growth under the well-watered growth condition than those of control plants. Decreases in the photosynthesis rate and stomatal conductance from ambient to higher VPD were slightly higher in transgenic plants than those in control plants. When plants were grown under the soil water deficit condition, decreases in the photosynthesis rate and stomatal conductance were less significant in transgenic plants than those in control plants. McMIPB is likely to work as a CO2 transporter, as well as control the regulation of stomata to water deficits.

  10. Rate and duration of seed filling and yield of soybean affected by water and radiation deficits

    Directory of Open Access Journals (Sweden)

    Kazem GHASSEMI-GOLEZANI

    2015-11-01

    Full Text Available Seed filling and yield of soybean under water and radiation deficits were investigated during 2011 and 2012. Treatments were irrigations (I1, I2, I3 and I4 for irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively in main plots and light interceptions (L1: 100 %, L2: 65 % and L3: 25 % sunlight in sub-plots. Seeds per plant under I1 and I2 decreased, but under I3 and I4 increasedas a result of radiation deficit. Maximum seed weight and seed filling duration of plants under 25 % light interception (L3 were higher than those under full sunlight (L1 and 65 % light interception (L2. In contrast, plants under full sunlight had the highest seed filling rate, particularly under water stress. Seed filling duration under severe light deficit (L3 was about 9 days longer than that under full sunlight (L1, leading to 15.8 % enhancement in maximum seed weight. Decreasing seed yield of soybean under well watering and mild water stress and improving it under moderate and severe water deficit due to low solar radiation are directly related with changes in seed filling duration and consequently in seed weight and number of seeds per plant under these conditions.

  11. Effects of drought and changes in vapour pressure deficit on water relations of Populusdeltoides growing in ambient and elevated CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bobich, E.G.; Barron-Gafford, G.A.; Rascher, K.G. [Columbia Univ., Oracle, AZ (United States). Biosphere 2 Center; Murthy, R. [Columbia Univ., Oracle, AZ (United States). Biosphere 2 Center, Earth and Environmental Sciences, Lamont-Doherty Earth Observatory

    2010-07-15

    According to the Intergovernmental Panel on Climate Change (IPCC), changes in the earth's climate are expected to become more extreme as carbon dioxide (CO{sub 2}) concentrations increase over the next century. This study examined the means by which growth CO{sub 2} concentration affects anatomy and water relation responses to drought and vapour pressure deficit (VPD). Yearly coppiced, 4-year-old Populus deltoides clones grown in either ambient or elevated CO{sub 2} for 3 years were examined to determine if trees growing in elevated CO{sub 2} during drought would have a lower volume flux density of water (JV), stomatal conductance (gs) and transpiration per leaf area (E), as well as a lower stomatal density and a greater stomatal response to drought and changes in VPD than would trees in ambient CO{sub 2}. The study showed that trees in elevated CO{sub 2} actually had higher JV values, but did not differ from trees in ambient CO{sub 2} in terms of gs or E under saturating light or E scaled from JV. The higher JV in elevated CO{sub 2} was attributed to the greater leaf area in the trees and not from differences in gs. Plants in elevated CO{sub 2} had greater absolute leaf loss during the drought, but the percentage of leaf area lost was similar to that of trees in ambient CO{sub 2}. Under saturating light, gs and E were influenced by changes in VPD after the first 9 days of the experiment, which coincided with a large decrease in water potential. It was concluded that longer-term growth of P. deltoides clone under elevated CO{sub 2} did not improve the effects of drought and high VPD on plant and water relations. 56 refs., 3 tabs., 4 figs.

  12. Changes in olive oil volatile organic compounds induced by water status and light environment in canopies of Olea europaea L. trees.

    Science.gov (United States)

    Benelli, Giovanni; Caruso, Giovanni; Giunti, Giulia; Cuzzola, Angela; Saba, Alessandro; Raffaelli, Andrea; Gucci, Riccardo

    2015-09-01

    Light and water are major factors in fruit development and quality. In this study, the effect of water and light in Olea europaea trees on volatile organic compounds (VOCs) in olive oil was studied over 2 years. Mature fruits were harvested from three zones of the canopy with different light exposure (64%, 42% and 30% of incident light) of trees subjected to full, deficit or complementary irrigation. VOCs were determined by SPME GC-MS and analysed by principal component analysis followed by discriminant analysis to partition treatment effects. Fruit fresh weight and mesocarp oil content decreased in zones where intercepted light was less. Low light levels significantly slowed down fruit maturation, whereas conditions of water deficit accelerated the maturation process. The presence of cyclosativene and α-muurulene was associated with water deficit, nonanal, valencene with full irrigation; α-muurulene, (E)-2-hexanal were related to low light conditions, while trans-β-ocimene, α-copaene, (Z)-2-penten-1-ol, hexanal and nonanal to well exposed zones. The year strongly affected the VOC profile of olive oil. This is the first report on qualitative changes in VOCs induced by light environment and/or water status. This information is valuable to better understand the role of environmental factors on the sensory quality of virgin olive oil. © 2014 Society of Chemical Industry.

  13. Monitoring the Soil Water Availability of Young Urban Trees in Hamburg, Germany

    Science.gov (United States)

    Titel, Selina; Gröngröft, Alexander; Eschenbach, Annette

    2017-04-01

    In large cities numerous trees have to be planted each year to replace died off or cut down trees or for greening of constructed roads and newly built quarters. The typical age of planted trees is between five and fifteen years. Often the planting takes place in special planting pits to stimulate the tree growth under the restricted urban conditions. Consequently, trees are surrounded by different soil substrates: the soil from the nursery in the root ball, the special planting pit substrate and the surrounding urban soil which is often anthropogenic influenced. Being relocated in the city, trees have to cope with the warmer urban climate, the soil sealing and compaction and the low water storage capacity of the substrate. All factors together increase the probability of dry phases for roadside trees. The aim of this study is to monitor the soil water availability at sites of planted roadside trees during the first years after planting. Therefore, a measuring design was developed, which works automatically and takes the complex below ground structure of the soil into account. This approach consists of 13 soil water tension sensors inside and outside of each planting pit up to one meter depth connected to a data logger. The monitoring devices will finally be installed at 20 roadside trees (amongst others Quercus cerris, Quercus robur, Acer platanoides 'Fairview') in Hamburg, Germany, to identify phases of drought stress. The young trees were mainly planted in spring 2016. Data of the first year of measurements show, that the water tension varied between the different soil substrates and the depth. In the first year of tree growth in the city, soil in the tree root ball became significantly drier than the surrounding soil material. In late summer 2016 the water tension in the topsoil had the potential to cause drought stress below some trees.

  14. Water deficit and water surplus maps for Brazil, based on FAO Penman-Monteith potential evapotranspiration

    Directory of Open Access Journals (Sweden)

    Ronalton Evandro Machado

    2008-12-01

    Full Text Available The climatological water balance (CWB proposed by Thornthwaite and Mather (1957 is a useful tool for agricultural planning. This method requires the soil water holding capacity (SWHC, rainfall (R and potential evapotranspiration (PET data as input. Among the methods used to estimate PET, the one proposed by Thornthwaite (1948 is the simplest and the most used in Brazil, however it presents limitations of use, which is caused by its empirical relationships. When Thornthwaite PET method is used into the CWB, the errors associated to PET are transferred to the output variables, mainly water deficit (WD and water surplus (WS. As all maps of WD and WS for Brazil are based on Thornthwaite PET, the objective of this study was to produce new maps of these variables considering Penman-Monteith PET. For this purpose, monthly normal climate data base (1961-1990 from Brazilian Meteorological Service (INMET, with 219 locations in all country, was used. PET data were estimated by Thornthwaite (TH and FAO Penman-Monteith (PM methods. PET, from both methods, and R data were used to estimate the CWB for a SWHC of 100 mm, having as results actual ET (AET, WD and WS. Results obtained with PET from the two methods were compared by regression analysis. The results showed that TH method underestimated annual PM PET by 13% in 84% of the places. Such underestimation also led to AET and WD underestimations of 7% (in 69% of places and 40% (in 83% of places, respectively. For WS, the use of TH PET data in the CWB resulted in overestimations of about 80% in 78% of places. The differences observed in the CWB variables resulted in changes in the maps of WD and WS for Brazil. These new maps, based on PM PET, provide more accurate information, mainly for agricultural and hydrological planning and irrigation and drainage projects purposes.

  15. EAB induced tree mortality impacts ecosystem respiration and tree water use in an experimental forest

    Science.gov (United States)

    Charles E. Flower; Douglas J. Lynch; Kathleen S. Knight; Miquel A. Gonzales-Meler

    2011-01-01

    The invasive emerald ash borer (Agrilus planipennis Fairmaire, EAB) has been spreading across the forest landscape of the Midwest resulting in the rapid decline of ash trees (Fraxinus spp.). Ash trees represent a dominant riparian species in temperate deciduous forests of the Eastern United States (USDA FIA Database). Prior...

  16. Net ecosystem productivity, net primary productivity and ecosystem carbon sequestration in a Pinus radiata plantation subject to soil water deficit

    Energy Technology Data Exchange (ETDEWEB)

    Arneth, A.; Kelleher, F. M. [Lincoln Univ., Soil Sience Dept., Lincoln, (New Zealand); McSeveny, T. M. [Manaaki Whenua-Landcare Research, Lincoln, (New Zealand); Byers, J. N. [Almuth Arneth Landcare Research, Lincoln (New Zealand)

    1998-12-01

    Tree carbon uptake (net primary productivity excluding fine root turnover, NPP`) in pine trees growing in a region of New Zealand subject to summer soil water deficit was investigated jointly with canopy assimilation (A{sub c}) and ecosystem-atmosphere carbon exchange rate (net ecosystem productivity, NEP). Canopy assimilation and NEP were used to drive a biochemically-based and environmentally constrained model validated by seasonal eddy covariance measurements. Over a three year period with variable rainfall annual NPP` and NEP showed significant variations. At the end of the growing season, carbon was mostly allocated to wood, with nearly half to stems and about a quarter to coarse roots. On a biweekly basis NPP` lagged behind A{sub c}, suggesting the occurrence of intermediate carbon storage. On an annual basis, however the NPP`/A{sub c} ratio indicated a conservative allocation of carbon to autotrophic respiration. The combination of data from measurements with canopy and ecosystem carbon fluxes yielded an estimate of heterotrophic respiration (NPP`-NEP) of approximately 30 per cent of NPP` and 50 per cent NEP. The annual values of NEP and NPP` can also be used to derive a `best guess` estimate of the annual below-ground carbon turnover rate, assuming that the annual changes in the soil carbon content is negligible. 46 refs., 7 figs.

  17. The Response of Rice Root to Time Course Water Deficit Stress-Two Dimensional Electrophoresis Approach

    Directory of Open Access Journals (Sweden)

    Mahmood Toorchi

    2015-11-01

    Full Text Available Rice (Oryza sativa L. is the staple food of more than half of the population worldwide. Water deficit stress is one of the harsh limiting factors for successful production of crops. Rice during its growing period comes a cross different environmental hazards like drought stress. Recent advance in molecular physiology are promising for more progress in increasing rice yield by identification of novel candidate proteins for drought tolerance. To investigate the effect of water deficit on rice root protein expression pattern, an experiment was conducted in completely randomize design with four replications. With holding water for 24, 36 and 48 hours along with control constituted the experimental treatments. The experiment was conducted in growth chamber under controlled condition and root samples, after stress imposition, were harvested for two-dimensional electrophorese (2-DE. Proteome analysis of root tissue by 2-DE indicated that out of 135 protein spots diagnosed by Coomassie blue staining, 14 spots showed significant expression change under water deficit condition, seven of them at 1% and the other seven at 5% probability levels. Differentially changed proteins were taken into account for search in data bank using isoelectric point and molecular weight to identify the most probable responsive proteins. Up- regulation of ferredoxin oxidoreductase at first 24 hour after applying stress indicates the main role of this protein in reducing water deficit stress effects. On the other hand ribosomal proteins, GAP-3 and ATP synthase were down regulated under water deficit stress. Fructose 1,6-bisphosphate aldolase, glucose- 6-phosphate dehydrogenase and chitinase down regulated up to 36 h of stress imposition but, were later up- regulated by prolonging stress up to 48 h. It could be inferred the plant tries to decrease the effect of oxidative stress.

  18. Deficit irrigation and sustainable water-resource strategies in agriculture for China's food security.

    Science.gov (United States)

    Du, Taisheng; Kang, Shaozhong; Zhang, Jianhua; Davies, William J

    2015-04-01

    More than 70% of fresh water is used in agriculture in many parts of the world, but competition for domestic and industrial water use is intense. For future global food security, water use in agriculture must become sustainable. Agricultural water-use efficiency and water productivity can be improved at different points from the stomatal to the regional scale. A promising approach is the use of deficit irrigation, which can both save water and induce plant physiological regulations such as stomatal opening and reproductive and vegetative growth. At the scales of the irrigation district, the catchment, and the region, there can be many other components to a sustainable water-resources strategy. There is much interest in whether crop water use can be regulated as a function of understanding of physiological responses. If this is the case, then agricultural water resources can be reallocated to the benefit of the broader community. We summarize the extent of use and impact of deficit irrigation within China. A sustainable strategy for allocation of agricultural water resources for food security is proposed. Our intention is to build an integrative system to control crop water use during different cropping stages and actively regulate the plant's growth, productivity, and development based on physiological responses. This is done with a view to improving the allocation of limited agricultural water resources. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Deficit irrigation and sustainable water-resource strategies in agriculture for China’s food security

    Science.gov (United States)

    Du, Taisheng; Kang, Shaozhong; Zhang, Jianhua; Davies, William J.

    2015-01-01

    More than 70% of fresh water is used in agriculture in many parts of the world, but competition for domestic and industrial water use is intense. For future global food security, water use in agriculture must become sustainable. Agricultural water-use efficiency and water productivity can be improved at different points from the stomatal to the regional scale. A promising approach is the use of deficit irrigation, which can both save water and induce plant physiological regulations such as stomatal opening and reproductive and vegetative growth. At the scales of the irrigation district, the catchment, and the region, there can be many other components to a sustainable water-resources strategy. There is much interest in whether crop water use can be regulated as a function of understanding of physiological responses. If this is the case, then agricultural water resources can be reallocated to the benefit of the broader community. We summarize the extent of use and impact of deficit irrigation within China. A sustainable strategy for allocation of agricultural water resources for food security is proposed. Our intention is to build an integrative system to control crop water use during different cropping stages and actively regulate the plant’s growth, productivity, and development based on physiological responses. This is done with a view to improving the allocation of limited agricultural water resources. PMID:25873664

  20. Genetic variation of response to water deficit in parental genotypes ...

    African Journals Online (AJOL)

    dgomi

    variability of measured parameters was explained by the effects of line, treatment and their interaction with treatment factor recorded the ... experiments plants were terminated at the vegetative stage (Badri et al., 2011; Wang, ... collected in different regions that varied in soil composition, salinity and water availability were ...

  1. Effect of water deficit stress on proline contents, soluble sugars ...

    African Journals Online (AJOL)

    The objective of the present work was to determine the mechanisms of tolerance of four sunflower hybrids; H1 = Azargol, H2 = Alstar, H3 = Hysun 33 and H4 = Hysun 25 to water stress under three different levels of irrigation regimes; WD1 = irrigation after 50 mm (normal irrigation), WD2 = 100 mm (mild stress) and WD3 ...

  2. Controlling water deficit by osmolytes and enzymes: Enhancement ...

    African Journals Online (AJOL)

    Water stress accentuated sucrose synthase/phosphate synthase activities while sucrolytic enzymes namely; acid, neutral and sucrose synthase (cleavage) got repressed. Higher build up of sucrose and lower activity of amylase in root and shoot further decreased reducing sugar (glucose, fructose) content in stressed ...

  3. Impact of water deficit stress on growth and alkaloid content of ...

    African Journals Online (AJOL)

    Experiments were conducted to study the effect of water deficit stress on the growth and alkaloid content of different organs of Spigelia anthelmia (L), a medicinal plant used locally as an anthelminthic. Plants were subjected to 6 days drought at the early (EV plants) and late (LV plants) vegetative stages (30-35 and 52-57 ...

  4. Mean annual yield reductions of potato due to water deficits for Dutch weather conditions.

    NARCIS (Netherlands)

    Vos, J.; Groenwold, J.

    1987-01-01

    In The Netherlands drought causes occasional reductions in yield and quality of potatoes, especially on sandy soils. The mean annual yield loss determines the investments that can be made to prevent the losses. The mean annual loss is determined by the water deficit and the yield reduction per mm

  5. Functionally relevant climate variables for arid lands: Aclimatic water deficit approach for modelling desert shrub distributions

    Science.gov (United States)

    Thomas E. Dilts; Peter J. Weisberg; Camie M. Dencker; Jeanne C. Chambers

    2015-01-01

    We have three goals. (1) To develop a suite of functionally relevant climate variables for modelling vegetation distribution on arid and semi-arid landscapes of the Great Basin, USA. (2) To compare the predictive power of vegetation distribution models based on mechanistically proximate factors (water deficit variables) and factors that are more mechanistically removed...

  6. Hydrogel efficiency and physiological responses of seedless citrus cultivars seedlings under water deficit

    Directory of Open Access Journals (Sweden)

    Ester Alice Ferreira

    2014-04-01

    Full Text Available Water is a limiting factor in citrus development which makes hydric replacement a common practice in plantations where its distribution is scarce. The hydroretentor gel has been one of the available technologies for water supply to plants and may also be an alternative that contributes to the rational use of water for planting citrus seedlings. This study evaluated the efficiency of hydrogel as an alternative to minimize the effects of water deficit in seedlings of seedless cultivars of tangerines ('Ortanique', 'Okitsu' and 'Clemenules' and oranges ('Navelina', 'Navelate' and 'Lanelate', all grafted on Poncirus trifoliata. The experiment was carried out in a greenhouse, in a randomized blocks design, where plants with hydrogel were compared to plants under conventional irrigation and also to plants under water deficit, in a triple factorial arrangement. The rates of carbon liquid assimilation, stomatal conductance and transpiration and the ratio between internal and external CO2 concentrations were evaluated. It was verified that the effect of the hydrogel for maintaining the hydric status of citrus seedlings is variable and dependent on physiological mechanisms of response to water deficit. There was no response of 'Ortanique' and 'Navelate'seedlings to the hydrogel application. The hydrogel promoted the recovering and maintenance of the hydric status of 'Okitsu', 'Clemenules', 'Navelina' and 'Lanelate' seedlings, however, these cultivars were sensitive to changes in the water status, with considerable reduction of gas exchange.

  7. Development and reproduction of spider mites Tetranychus turkestani (Acari: Tetranychidae under water deficit condition in soybeans

    Directory of Open Access Journals (Sweden)

    Ivelina Nikolova

    2014-09-01

    Full Text Available One of the major pests of soybeans in Bulgaria is the spider mite Tetranychus turkestani Ug et Nik (Acari: Tetranychidae and different results have been reported about the impact of water stress on its development and reproduction. Soybean plants exposed to natural infestation by spider mites, water deficit and treatment with imidacloprid were examined under greenhouse conditions at the Institute of Forage Crops, Pleven, Bulgaria, over the period 2011-2012. The development of mites and their eggs was faster when plants were exposed to water deficit, which created favorable conditions for high density and reproduction of T. turkestani. There was a vertical distribution of protonymphs, deutonymphs and adults as their numbers and egg counts were significantly higher under conditions of water deficit on the upper and middle plant parts, compared with their bottom parts, and imidacloprid treatment had a stronger and more prolonged activity against mites, compared to its influence on well-watered plants. Spider mites on water-stressed plants caused a 24.8% reduction in the contents of plastid pigments, and carotenoids, and 21.5% decrease on well-watered plants.

  8. Effect of Foliar Application of Chitosan on Growth and Biochemical Characteristics of Safflower (Carthamus tinctorius L. under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    batool mahdavi

    2014-09-01

    Full Text Available In order to study the effects of water deficit stress and foliar application of chitosan in safflower (Carthamus tinctorius L., a pot experiment was conducted in 2009. Experimental design was a randomized complete block in factorial arrangement with three replications. Experimental factors were water deficit levels (unstressed (control and 70% available water depletion from soil (water deficit stress, chitosan concentrations (0, 0.05, 0.1%, all dissolved in 1% acetic acid along with an additional treatment of distilled water and foliar application times (before and during stem elongation. The results showed that water deficit stress reduced plant height, leaf area, shoot and root dry weight, root height and volume. Whereas, foliar application of chitosan increased mentioned traits. In addition, water deficit stress decreased chlorophyll fluorescence, chlorophyll concentration and relative water content. Carotenoid, proline and malondialdehyde (MDA content were increased in response to stress. Foliar application of chitosan increased chlorophyll fluorescence, relative water content (68.77% and chlorophyll b in the water deficit stressed plants, whereas decreased MDA content. The results of the present study indicate that application of chitosan can reduce the harmful effects of water deficit and improve plant growth.

  9. Profiling of sugar transporter genes in grapevine coping with water deficit.

    Science.gov (United States)

    Medici, Anna; Laloi, Maryse; Atanassova, Rossitza

    2014-11-03

    The profiling of grapevine (Vitis vinifera L.) genes under water deficit was specifically targeted to sugar transporters. Leaf water status was characterized by physiological parameters and soluble sugars content. The expression analysis provided evidence that VvHT1 hexose transporter gene was strongly down-regulated by the increased sugar content under mild water-deficit. The genes of monosaccharide transporter VvHT5, sucrose carrier VvSUC11, vacuolar invertase VvGIN2 and grape ASR (ABA, stress, ripening) were up-regulated under severe water stress. Their regulation in a drought-ABA signalling network and possible roles in complex interdependence between sugar subcellular partitioning and cell influx/efflux under Grapevine acclimation to dehydration are discussed. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  10. New phenotyping methods for screening wheat and barley for beneficial responses to water deficit.

    Science.gov (United States)

    Munns, Rana; James, Richard A; Sirault, Xavier R R; Furbank, Robert T; Jones, Hamlyn G

    2010-08-01

    This review considers stomatal conductance as an indicator of genotypic differences in the growth response to water stress. The benefits of using stomatal conductance are compared with photosynthetic rate and other indicators of genetic variation in water stress tolerance, along with the use of modern phenomics technologies. Various treatments for screening for genetic diversity in response to water deficit in controlled environments are considered. There is no perfect medium: there are pitfalls in using soil in pots, and in using hydroponics with ionic and non-ionic osmotica. Use of mixed salts or NaCl is recommended over non-ionic osmotica. Developments in infrared thermography provide new and feasible screening methods for detecting genetic variation in the stomatal response to water deficit in controlled environments and in the field.

  11. Responses to flooding of plant water relations and leaf gas exchange in tropical tolerant trees of a black-water wetland

    Directory of Open Access Journals (Sweden)

    Ana eHerrera

    2013-05-01

    Full Text Available This review summarizes the research on physiological responses to flooding of trees in the seasonal black-water wetland of the Mapire River in Venezuela. Inter-annual variability was found during eight years of sampling, in spite of which a general picture emerged of increased stomatal conductance (gs and photosynthetic rate (PN during the flooded period to values as high as or higher than in plants in drained wet soil. Models explaining the initial inhibitory responses and the acclimation to flooding are proposed. In the inhibitory phase of flooding, hypoxia generated by flooding causes a decrease in root water absorption and stomatal closure. An increase with flooding in xylem water potential ( suggests that flooding does not cause water deficit. The PN decreases due to changes in relative stomatal and non-stomatal limitations to photosynthesis; an increase in the latter is due to reduced chlorophyll and total soluble protein content. Total non-structural carbohydrates accumulate in leaves but their content begins to decrease during the acclimatized phase at full flooding, coinciding with the resumption of high gs and PN. The reversal of the diminution in gs is associated, in some but not all species, to the growth of adventitious roots. The occurrence of morpho-anatomical and biochemical adaptations which improve oxygen supply would cause the acclimation, including increased water absorption by the roots, increased rubisco and chlorophyll contents and ultimately increased PN. Therefore, trees would perform as if flooding did not signify a stress to their physiology.

  12. Effect of Water Deficit Stress on Peach Growth under Commercial Orchard Management Conditions

    OpenAIRE

    Rahmati, M; Gh. Davarynejad; M. Bannayan Awal; Azizi, M

    2015-01-01

    In order to study the sensitivity of vegetative growth to water deficit stress of a late-maturing peach (Prunus persica L. cv. Elberta) under orchard conditions, an experiment was conducted as randomized complete-block design with three treatments and four repetitions in Shahdiran commercial orchard in Mashhad during 2011. Three irrigation treatments including 360 (low stress), 180 (moderate stress) and 90 (severe stress) m3ha-1week-1 using a drip irrigation system (minimum stem water potenti...

  13. Hydrolysis kinetics of tulip tree xylan in hot compressed water.

    Science.gov (United States)

    Yoon, Junho; Lee, Hun Wook; Sim, Seungjae; Myint, Aye Aye; Park, Hee Jeong; Lee, Youn-Woo

    2016-08-01

    Lignocellulosic biomass, a promising renewable resource, can be converted into numerous valuable chemicals post enzymatic saccharification. However, the efficacy of enzymatic saccharification of lignocellulosic biomass is low; therefore, pretreatment is necessary to improve the efficiency. Here, a kinetic analysis was carried out on xylan hydrolysis, after hot compressed water pretreatment of the lignocellulosic biomass conducted at 180-220°C for 5-30min, and on subsequent xylooligosaccharide hydrolysis. The weight ratio of fast-reacting xylan to slow-reacting xylan was 5.25 in tulip tree. Our kinetic results were applied to three different reaction systems to improve the pretreatment efficiency. We found that semi-continuous reactor is promising. Lower reaction temperatures and shorter space times in semi-continuous reactor are recommended for improving xylan conversion and xylooligosaccharide yield. In the theoretical calculation, 95% of xylooligosaccharide yield and xylan conversion were achieved simultaneously with high selectivity (desired product/undesired product) of 100 or more. Copyright © 2016. Published by Elsevier Ltd.

  14. Evidence of hydraulic lift for pre-rainy season leaf out and dry-season stem water enrichment in Sclerocarya birrea, a tropical agroforestry tree

    Science.gov (United States)

    Ceperley, Natalie; Mande, Theophile; Rinaldo, Andrea; Parlange, Marc B.

    2014-05-01

    We use stable isotopes of water as tracers to follow water use by five Sclerocarya birrea trees in a catchment in South Eastern Burkina Faso interspersed with millet fields, gallery forest, Sudanian savanna, and fallow fields. Isotopic ratios were determined from water extracted from stems of the trees and sub-canopy soil of two of them, while nearby ground water, precipitation, and surface water was sampled weekly. A unique configuration of sensors connected with a wireless sensor network of meteorological stations measured sub-canopy shading, the temperature and humidity in the canopy, through-fall, and soil moisture under two of the trees. Both water extracted from sap and water extracted from soil is extremely enriched in the dry season, but drop to levels close to the ground water in February or March, which coincides with the growth of leaves. Dates of leaf out were confirmed by changes in δDH and δO18 concentrations of water, photographic documentation & pixel analysis, and analysis of sub-canopy radiation and proceeded the rise in humidity and flow that was later detected in the sub-canopy soil, the trunk of the tree (sap-flow), and atmosphere (canopy VPD). Examination of the isotopic signature suggests that size of tree plays an important role in duration and timing of this leaf-out as well as the degree of enrichment during the peak of the dry season. Further examination of the isotopic signatures of the roots suggested that the trees are performing hydraulic redistribution, or lifting the ground water and "sharing it" with the soil in the rooting zone in the dry season. The enriched level of xylem in this case is a product of water loss, and enrichment, along the travel path of the water from the roots to the tip of the stem, as evidenced by the variation according to size of tree. Vapor pressure deficit, soil water, and soil moisture interactions support this picture of interacting controls, separate from hydrologic triggers on the water movement in

  15. Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices

    Science.gov (United States)

    Stagakis, S.; González-Dugo, V.; Cid, P.; Guillén-Climent, M. L.; Zarco-Tejada, P. J.

    2012-07-01

    This paper deals with the monitoring of water status and the assessment of the effect of stress on citrus fruit quality using structural and physiological remote sensing indices. Four flights were conducted over a citrus orchard in 2009 using an unmanned aerial vehicle (UAV) carrying a multispectral camera with six narrow spectral bands in the visible and near infrared. Physiological indices such as the Photochemical Reflectance Index (PRI570), a new structurally robust PRI formulation that uses the 515 nm as the reference band (PRI515), and a chlorophyll ratio (R700/R670) were compared against the Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI) and Modified Triangular Vegetation Index (MTVI) canopy structural indices for their performance in tracking water status and the effects of sustained water stress on fruit quality at harvest. The irrigation setup in the commercial orchard was compared against a treatment scheduled to satisfy full requirements (based on estimated crop evapotranspiration) using two regulated deficit irrigation (RDI) strategies. The water status of the trees throughout the experiment was monitored with frequent field measurements of stem water potential (Ψx), while titratable acidity (TA) and total soluble solids (TSS) were measured at harvest on selected trees from each irrigation treatment. The high spatial resolution of the multispectral imagery (30 cm pixel size) enabled identification of pure tree crown components, extracting the tree reflectance from shaded, sunlit and aggregated pixels. The physiological and structural indices were then calculated from each tree at the following levels: (i) pure sunlit tree crown, (ii) entire crown, aggregating the within-crown shadows, and (iii) simulating a lower resolution pixel, including tree crown, sunlit and shaded soil pixels. The resulting analysis demonstrated that both PRI formulations were able to track water status, except when water stress

  16. Soil hydrology of agroforestry systems: Competition for water or positive tree-crops interactions?

    Science.gov (United States)

    Gerjets, Rowena; Richter, Falk; Jansen, Martin; Carminati, Andrea

    2017-04-01

    In dry periods during the growing season crops may suffer from severe water stress. The question arises whether the alternation of crop and tree strips might enhance and sustain soil water resources available for crops during drought events. Trees reduce wind exposure, decreasing the potential evapotranspiration of crops and soils; additionally hydraulic lift from the deep roots of trees to the drier top soil might provide additional water for shallow-rooted crops. To understand the above and belowground water relations of agroforestry systems, we measured soil moisture and soil water potential in crop strips as a function of distance to the trees at varying depth as well as meteorological parameters. At the agroforestry site Reiffenhausen, Lower Saxony, Germany, two different tree species are planted, each in one separated tree strip: willow breed Tordis ((Salix viminalis x Salix Schwerinii) x Salix viminalis) and poplar clone Max 1 (Populus nigra x Populus maximowiczii). In between the tree strips a crop strip of 24 m width was established with annual crop rotation, managed the same way as the reference site. During a drought period in May 2016 with less than 2 mm rain in four weeks, an overall positive effect on hydrological conditions of the agroforestry system was observed. The results show that trees shaded the soil surface, lowering the air temperature and further increasing the soil moisture in the crop strips compared to the reference site, which was located far from the trees. At the reference site the crops took up water in the upper soil (<20 cm depth); after the soil reached water potentials below -100 kPa, root water uptake moved to deeper soil layers (<40 cm). Because of the higher wind and solar radiation exposure the reference soil profile was severely dried out. Also in the crop strips of the agroforestry system, crops took up water in the upper soil. However, the lower soil layers remained wet for an extended period of time. The tree strips

  17. Antioxidative responses, physiological and productive of rice grown under water deficit and silicon fertilization

    Directory of Open Access Journals (Sweden)

    Adriana Lima Moro

    2015-10-01

    Full Text Available Silicon is a nutrient that can provide better development of rice plants grown in environments with water deficit. This element reduces water loss by transpiration, increases photosynthetic rate and acts as an activator of the enzyme defense system. The purpose of this research was analyse the effect of silicon in two rice cultivars (Curinga and IAC 202 submitted to water deficit under the enzymatic parameters, physiological and productive. We used four strains of soil water (-10, –30, –50 and –70 kPa combined with two ways of correcting the soil saturation (absence and presence of silicon. We measured the enzymatic activity of Superoxide dismutase, catalase and ascorbate peroxidase, the rate of CO2 assimilation and yield. The experimental design was randomized in blocks 4 x 2 factorial with four replications, and the means compared by Tukey test (p <0.05. The enzyme activity increased with the application of silicon even in intense water deficit. The CO2 assimilation rate and also grain yield increased with the addition of silicon. The application of silicone on both cultivars alleviate the effects of stress caused by lack of water.

  18. Plant response to environmental conditions: assessing potential production, water demand and negative effects of water deficit

    Directory of Open Access Journals (Sweden)

    Francois eTardieu

    2013-02-01

    Full Text Available This paper reviews methods for analyzing plant performance and its genetic variability under a range of environmental conditions. Biomass accumulation is linked every day to available light in the PAR domain, multiplied by the proportion of light intercepted by plants and by the radiation use efficiency. Total biomass is cumulated over the duration of the considered phase (e.g. plant cycle or vegetative phase. These durations are essentially constant for a given genotype provided that time is corrected for temperature (thermal time. Several ways of expressing thermal time are reviewed. Two alternative equations are presented, based either on the effect of transpiration, or on yield components. Their comparative interests and drawbacks are discussed. The genetic variability of each term of considered equations affects yield under water deficit, via mechanisms at different scales of plant organisation and time. The effect of any physiological mechanism on yield of stressed plants acts via one of these terms, although the link is not always straightforward. Finally, I propose practical ways to compare of the productivity of genotypes in field environments, and a ‘minimum dataset’ of environmental data and traits that should be recorded for that.

  19. Molecular, physiological and biochemical responses of Theobroma cacao L. genotypes to soil water deficit.

    Science.gov (United States)

    Santos, Ivanildes C Dos; Almeida, Alex-Alan Furtado de; Anhert, Dário; Conceição, Alessandro S da; Pirovani, Carlos P; Pires, José L; Valle, Raúl René; Baligar, Virupax C

    2014-01-01

    Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (ΨWL) ranging from -0.1 to -0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ΨWL reached values of between -2.0 to -2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought.

  20. Development of maize and palisadegrass plants cultivated in intercrop under water deficit

    Directory of Open Access Journals (Sweden)

    Leandro Coelho de Araujo

    2011-07-01

    Full Text Available The objective of this work was to evaluate the development and productive traits of palisadegrass single cultivated or intercropped with corn, in addition to corn intercropped with pasture, under water deficit at different development stages of the plants. It was used a complete block experimental design with split plots and three replicates. Periods of water deficit were placed in the plots and types of cultivation were placed in the subplots. Irrigation was stopped at germination and initial tillering of palisadegrass and at V4 and V15 stages of corn and returned when soil moisture was 40% of available water capacity. Tiller density and palisadegrass height were evaluated weekly. Dry matter (DM of fractions of herbage mass as well as leaf area of the plants were evaluated at corn tasseling and when grains reached physiological maturity. Components of corn production were determined in the second sampling. In palisadegrass, water influenced only tillering, which was reduced in the plots in which water defict was forced at the moment of germination or at the beginning of tilering, in both cultivation systems. Plant height and DM production were affected only by cultivation, reducing when intercropped with corn. Evaluated production components did not influence corn grain productivity, which was similar in all treatments (average of 10,145 kg/ha. Palisadegrass plants produce more DM in single cultivation than intercropped with corn. Water deficit during germination and initial tillering reduces tillering of palisadegrass during establishment phase. Water deficit, applied in this trial, does not reduce DM yield in palisadegrass or corn.

  1. Public participation and rural management of Brazilian waters: an alternative to the deficit model

    Directory of Open Access Journals (Sweden)

    Alessandro Luís Piolli

    2008-12-01

    Full Text Available The knowledge deficit model with regard to the public has been severely criticized in the sociology of the public perception of science. However, when dealing with public decisions regarding scientific matters, political and scientific institutions insist on defending the deficit model. The idea that only certified experts, or those with vast experience, should have the right to participate in decisions can bring about problems for the future of democracies. Through a type of "topography of ideas", in which some concepts from the social studies of science are used in order to think about these problems, and through the case study of public participation in the elaboration of the proposal of discounts in the fees charged for rural water use in Brazil, we will try to point out an alternative to the deficit model. This alternative includes a "minimum comprehension" of the scientific matters involved in the decision on the part of the participants, using criteria judged by the public itself.

  2. Tree-Level Hydrodynamic Approach for Modeling Aboveground Water Storage and Stomatal Conductance Highlights the Effects of Tree Hydraulic Strategy

    Science.gov (United States)

    Mirfenderesgi, G.; Bohrer, G.; Matheny, A. M.; Fatichi, S.; Frasson, R. P. M.; Schafer, K. V.

    2016-12-01

    The Finite-difference Ecosystem-scale Tree-Crown Hydrodynamics model version 2 (FETCH2) is a novel tree-scale hydrodynamic model of transpiration. The FETCH2 model employs a finite difference numerical methodology and a simplified single-beam conduit system and simulates water flow through the tree as a continuum of porous media conduits. It explicitly resolves xylem water potential throughout the tree's vertical extent. Empirical equations relate water potential within the stem to stomatal conductance of the leaves at each height throughout the crown. While highly simplified, this approach brings additional realism to the simulation of transpiration by linking stomatal responses to stem water potential rather than directly to soil moisture, as is currently the case in the majority of land-surface models. FETCH2 accounts for plant hydraulic traits, such as the degree of anisohydric/isohydric response of stomata, maximal xylem conductivity, vertical distribution of leaf area, and maximal and minimal stemwater content. We used FETCH2 along with sap flow and eddy covariance data sets collected from a mixed plot of two genera (oak/pine) in Silas Little Experimental Forest, NJ, USA, to conduct an analysis of the inter-genera variation of hydraulic strategies and their effects on diurnal and seasonal transpiration dynamics. We define these strategies through the parameters that describe the genus-level transpiration and xylem conductivity responses to changes in stem water potential. A virtual experiment showed that the model was able to capture the effect of hydraulic strategies such as isohydric/anisohydric behavior on stomatal conductance under different soil-water availability conditions. Our evaluation revealed that FETCH2 considerably improved the simulation of ecosystem transpiration and latent heat flux than more conventional models.

  3. Pb and Cd Contents in Soil, Water, and Trees at an Afforestation Site, South China.

    Science.gov (United States)

    Pei, Nancai; Chen, Bufeng; Liu, Shuguang

    2015-11-01

    Pb and Cd contents in 13 plantation tree species (leaf and branch components), soil, water (groundwater and river water) at a young (3-5 year-old) seashore afforestation stand were investigated in Nansha district, Guangzhou city in southern China. The results showed that (1) soil, rather than water or trees, had the highest content of both Pb (averagely 48.79 mg/kg) and Cd (0.50 mg/kg), demonstrating that soil might function as a major reservoir for extraneously derived heavy metals; (2) Pb content was higher in branches than in leaves, but Cd content appeared similar in both components, implying possibly different accumulation mechanisms in trees; (3) Pb and Cd appeared to accumulate differently among some tree taxa, whereas almost no significant difference was detected between introduced and indigenous species. The study indicated that trees were potentially useful to remediate sites contaminated with Pb and Cd in the urbanized areas.

  4. Water deficit stress-induced changes in carbon and nitrogen partitioning in Chenopodium quinoa Willd.

    Science.gov (United States)

    Bascuñán-Godoy, Luisa; Reguera, Maria; Abdel-Tawab, Yasser M; Blumwald, Eduardo

    2016-03-01

    Water deficit stress followed by re-watering during grain filling resulted in the induction of the ornithine pathway and in changes in Quinoa grain quality. The genetic diversity of Chenopodium quinoa Willd. (Quinoa) is accompanied by an outstanding environmental adaptability and high nutritional properties of the grains. However, little is known about the biochemical and physiological mechanisms associated with the abiotic stress tolerance of Quinoa. Here, we characterized carbon and nitrogen metabolic changes in Quinoa leaves and grains in response to water deficit stress analyzing their impact on the grain quality of two lowland ecotypes (Faro and BO78). Differences in the stress recovery response were found between genotypes including changes in the activity of nitrogen assimilation-associated enzymes that resulted in differences in grain quality. Both genotypes showed a common strategy to overcome water stress including the stress-induced synthesis of reactive oxygen species scavengers and osmolytes. Particularly, water deficit stress induced the stimulation of the ornithine and raffinose pathways. Our results would suggest that the regulation of C- and N partitioning in Quinoa during grain filling could be used for the improvement of the grain quality without altering grain yields.

  5. Impact of water deficit stress on biochemical characteristics of safflower cultivars.

    Science.gov (United States)

    Sajedi, N A; Ferasat, M; Mirzakhani, M; Boojar, M Mashhadi Akbar

    2012-10-01

    Water deficit stress is one of the severe limitations of crop growth especially in arid and semiarid regions of the world as it effect the plant growth at all stages of development. In the present study, four safflower genotypes Esfahan native, Esfahan-14, PI537,598 and IL111 were tested for their growth and crop yield under water-deficit stress. A detailed biochemical analysis was carried out at various levels of irrigation to find out the genotypic variation and the activity of several enzymes known to play significant role under drought stress. A split plot experiment based on randomized complete blocks design was conducted at three levels of irrigation: 100 % (normal water requirement for safflower), 75 % and 50 %. A significant increase in the activity of SOD, CAT, GPX enzymes and the levels of ABA and proline was observed with an increase in the water stress level in the leaves of all the genotypes investigated. The highest increase in the activities of antioxidant enzymes and proline and ABA content with reduced electrolyte leakage was observed in the relatively drought tolerance native Esfahan cultivar. These results suggest that the cultivars that exhibit highest levels of antioxidant enzymes activity and proline and ABA content under water deficit conditions may provide better drought tolerance in safflower.

  6. Trees

    Directory of Open Access Journals (Sweden)

    Henri Epstein

    2016-11-01

    Full Text Available An algebraic formalism, developed with V. Glaser and R. Stora for the study of the generalized retarded functions of quantum field theory, is used to prove a factorization theorem which provides a complete description of the generalized retarded functions associated with any tree graph. Integrating over the variables associated to internal vertices to obtain the perturbative generalized retarded functions for interacting fields arising from such graphs is shown to be possible for a large category of space–times.

  7. Surface water storage capacity of twenty tree species in Davis, California

    Science.gov (United States)

    Qingfu Xiao; E. Gregory. McPherson

    2016-01-01

    Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage...

  8. Hydraulic redistribution of water from Pinus ponderosa trees to seedlings: evidence for an ectomycorrhizal pathway.

    Science.gov (United States)

    Jeffrey M. Warren; J. Renee Brooks; Frederick C. Meinzer; Joyce L. Eberhart

    2008-01-01

    Although there is strong evidence for hydraulic redistribution (HR) of soil water by trees, it is not known if common myconhizal networks (CMN) can facilitate HR from mature trees to seedlings under field conditions. Ponderosa pine (Pinus ponderosa) seedlings were planted into root-excluding 61-micron mesh barrier chambers buried in an old-growth...

  9. Photochemical and antioxidant responses in the leaves of Xerophyta viscosa Baker and Digitaria sanguinalis L. under water deficit.

    Science.gov (United States)

    Ekmekci, Yasemin; Bohms, Andreas; Thomson, Jennifer A; Mundree, Sagadevan G

    2005-01-01

    In this study, photochemical and antioxidant responses of the monocotyledonous resurrection plant Xerophyta viscosa Baker and the crab grass Digitaria sanguinalis L. under water deficit were investigated as a function of time. Water deficit was imposed by withholding irrigation for 21 d. Gas exchange and chlorophyll a fluorescence analyses indicated that the dehydration treatment caused photoinhibition in both species. The reduction in the photosynthesis rate in both species during water deficit probably contributed to the decline in the photochemical efficiency of PSII and electron transport rate. However, the stomatal conductance of both species did not change during treatment whereas the intercellular CO2 pressure increased after 10 d of water deficit treatment. These observations could be related to nonstomatal limitations. The increasing net transpiration rate of both species may have contributed to leaf cooling because of water limitations. Prolonged water deficit resulted in photosynthetic pigment chlorophyll (a + b) and carotenoids content loss in only D. sanguinalis. Both species especially D. sanguinalis had increased the level of anthocyanin after 15 d of treatment, possibly to prevent the damaging effect of photooxidation. The total SOD activity of D. sanguinalis was significantly different from X. viscosa during the treatment. The total peroxidase activity in D. sanguinalis was significantly higher than in X. viscosa. X. viscosa acclimated to water deficit with no ultimate apparent oxidative damage due to endogenous protective mechanisms of resurrection. In case of D. sanguinalis, water deficit induced considerable stress and possibly caused some oxidative damage, despite the upregulation of protection mechanisms.

  10. Physiological mechanisms contributing to the increased water-use efficiency in winter wheat under deficit irrigation.

    Science.gov (United States)

    Xue, Qingwu; Zhu, Zixi; Musick, Jack T; Stewart, B A; Dusek, Donald A

    2006-02-01

    Deficit irrigation in winter wheat has been practiced in the areas with limited irrigation water resources. The objectives of this study were to (i) understand the physiological basis for determinations of grain yield and water-use efficiency in grain yield (WUE) under deficit irrigation; and (ii) investigate the effect of deficit irrigation on dry matter accumulation and remobilization of pre-anthesis carbon reserves during grain filling. A field experiment was conducted in the Southern High Plains of the USA and winter wheat (cv. TAM 202) was grown on Pullman clay loam soil (fine mixed thermic Torretic Paleustoll). Treatments consisted of rain-fed, deficit irrigation from jointing to the middle of grain filling, and full irrigation. The physiological measurements included leaf water potential, net photosynthetic rate (Pn), stomatal conductance (Gs), and leaf area index. The rain-fed treatment had the lowest seasonal evapotranspiration (ET), biomass, grain yield, harvest index (HI) and WUE as a result of moderate to severe water stress from jointing to grain filling. Irrigation application increased seasonal ET, and ET increased as irrigation frequency increased. The seasonal ET increased 20% in one-irrigation treatments between jointing and anthesis, 32-46% in two-irrigation treatments, and 67% in three- and full irrigation treatments. Plant biomass, grain yield, HI and WUE increased as the result of increased ET. The increased yield under irrigation was mainly contributed by the increased number of spikes, and seeds per square meter and per spike. Among the irrigation treatments, grain yield increased significantly but the WUE increased slightly as irrigation frequency increased. The increased WUE under deficit irrigation was contributed by increased HI. Water stress during grain filling reduced Pn and Gs, and accelerated leaf senescence. However, the water stress during grain filling induced remobilization of pre-anthesis carbon reserves to grains, and the

  11. Separate and combined responses to water deficit and UV-B radiation.

    Science.gov (United States)

    Bandurska, Hanna; Niedziela, Justyna; Chadzinikolau, Tamara

    2013-12-01

    Crops and other plants in natural conditions are routinely affected by several stresses acting simultaneously or in sequence. In areas affected by drought, plants may also be exposed to enhanced UV-B radiation (280-315nm). Each of these stress factors differently affects cellular metabolism. A common consequence of plant exposure to the separate action of water deficit and UV-B radiation is the enhanced generation of reactive oxygen species (ROS) causing damage to proteins, lipids, carbohydrates and DNA. Despite this destructive activity, ROS also act as signalling molecules in cellular processes responsible for defence responses. Plants have evolved many physiological and biochemical mechanisms that avoid or tolerate the effects of stress factors. Water deficit avoidance leads to stomatal closure, stimulation of root growth, and accumulation of free proline and other osmolytes. Secondary metabolites (flavonols, flavones and anthocyanins) that accumulate in epidermal cells effectively screen UV-B irradiation and reduce its penetration to mesophyll tissue. The coordinated increased activity of the enzymatic antioxidant defence system such as up-regulation of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and glutathione reductase is an important mechanism of tolerance to water deficit and UV-B radiation. The accumulation of low molecular antioxidants (proline, glycine betaine, ascorbate and glutathione) can also contribute to tolerance to water deficit. Polyamines, tocopherol, carotenoids, alkaloids, flavonoids and other secondary metabolites participate in the removal of ROS under conditions of increased UV-B radiation. The combination of water deficit and UV-B radiation induces responses that can be antagonistic, additive or synergistic in comparison with the action of single stresses. UV-B radiation may enhance resistance to water deficit and vice versa. Hydrogen peroxide, nitric oxide (NO), abscisic acid (ABA), jasmonic acid, ethylene

  12. Effects of drought and changes in vapour pressure deficit on water relations of Populus deltoides growing in ambient and elevated CO2.

    Science.gov (United States)

    Bobich, Edward G; Barron-Gafford, Greg A; Rascher, Katherine G; Murthy, Ramesh

    2010-07-01

    The means by which growth CO(2) concentration ([CO(2)]) affects anatomy and water relations responses to drought and vapour pressure deficit (VPD) were studied for yearly coppiced, 4-year-old Populus deltoides clones that were grown in either 400 mumol mol(-1) (ambient) or 800 mumol mol(-1) (elevated) CO(2) for 3 years. It was hypothesized that, during drought, trees growing in elevated [CO(2)] would have a lower volume flux density of water (J(V)), stomatal conductance (g(s)) and transpiration per leaf area (E), as well as a lower stomatal density and a greater stomatal response to drought and changes in VPD than would trees in ambient [CO(2)]. Trees in elevated [CO(2)] actually had higher J(V) values throughout the study, but did not differ from trees in ambient [CO(2)] with respect to g(s) or E under saturating light or E scaled from J(V) (E(scaled)), all of which indicates that the higher J(V) in elevated [CO(2)] resulted from those trees having greater leaf area and not from differences in g(s). Furthermore, although plants in elevated [CO(2)] had greater absolute leaf loss during the drought, the percentage of leaf area lost was similar to that of trees in ambient [CO(2)]. g(s) and E under saturating light were affected by changes in VPD after the first 9 days of the experiment, which coincided with a large decrease in water potential at a soil depth of 0.1 m. Trees in elevated [CO(2)] had a greater stomatal density and a lower wood density than trees in ambient [CO(2)], both traits that may make the trees more susceptible to xylem cavitation in severe drought. Drought and VPD effects for the P. deltoides clone were not ameliorated by long-term growth in elevated [CO(2)] compared with ambient [CO(2)], and plants in elevated [CO(2)] possessed anatomical traits that may result in greater stress associated with long-term drought.

  13. Controlled water deficit during ripening affects proanthocyanidin synthesis, concentration and composition in Cabernet Sauvignon grape skins.

    Science.gov (United States)

    Cáceres-Mella, Alejandro; Talaverano, M Inmaculada; Villalobos-González, Luis; Ribalta-Pizarro, Camila; Pastenes, Claudio

    2017-08-01

    The influence of controlled water deficit on the phenolic composition and gene expression of VvLAR2, VvMYBPA1, VvMYBPA2 and VvMYB4a in Cabernet Sauvignon grape skins throughout ripening was investigated. The assay was carried out on own-rooted Vitis vinifera plants cv. Cabernet Sauvignon in a commercial vineyard from veraison until commercial harvest. Three irrigation regimes were used from veraison until harvest with the following treatments: T1: 3.6 mm day -1 ; T2: 1.8 mm day -1 and T3: 0.3 mm day -1 . The content of total phenols and total anthocyanins in grape skins increased during ripening, but water deficit did not produce differences among treatments in the total anthocyanin concentration. Proanthocyanidins (PAs) decreased throughout ripening, although approximately 25 days after veraison (DAV), their content slightly increased. This effect was more pronounced in the most restrictive treatment (T3). A similar pattern was observed in the transcript abundance of VvLAR2, VvMYBPA1 and VvMYB4a. PAs separation revealed differences in concentration but not in the proportion among fractions among the irrigation treatments. Additionally, controlled water deficit increased the mean degree of polymerization and the flavan-3-ol polymeric concentration in grape skins throughout ripening but with no effects on the extent of PAs galloylation. Our results suggest that the water status of Cabernet Sauvignon grapevines affects the gene expression for proteins involved in the synthesis of PAs, increasing their concentration and also their composition, with further evidence for the efficacy of a convenient, controlled water deficit strategy for grapevine cultivation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Interact to Survive: Phyllobacterium brassicacearum Improves Arabidopsis Tolerance to Severe Water Deficit and Growth Recovery

    Science.gov (United States)

    Bresson, Justine; Vasseur, François; Dauzat, Myriam; Labadie, Marc; Varoquaux, Fabrice; Touraine, Bruno; Vile, Denis

    2014-01-01

    Mutualistic bacteria can alter plant phenotypes and confer new abilities to plants. Some plant growth-promoting rhizobacteria (PGPR) are known to improve both plant growth and tolerance to multiple stresses, including drought, but reports on their effects on plant survival under severe water deficits are scarce. We investigated the effect of Phyllobacterium brassicacearum STM196 strain, a PGPR isolated from the rhizosphere of oilseed rape, on survival, growth and physiological responses of Arabidopsis thaliana to severe water deficits combining destructive and non-destructive high-throughput phenotyping. Soil inoculation with STM196 greatly increased the survival rate of A. thaliana under several scenarios of severe water deficit. Photosystem II efficiency, assessed at the whole-plant level by high-throughput fluorescence imaging (Fv/Fm), was related to the probability of survival and revealed that STM196 delayed plant mortality. Inoculated surviving plants tolerated more damages to the photosynthetic tissues through a delayed dehydration and a better tolerance to low water status. Importantly, STM196 allowed a better recovery of plant growth after rewatering and stressed plants reached a similar biomass at flowering than non-stressed plants. Our results highlight the importance of plant-bacteria interactions in plant responses to severe drought and provide a new avenue of investigations to improve drought tolerance in agriculture. PMID:25226036

  15. Interact to survive: Phyllobacterium brassicacearum improves Arabidopsis tolerance to severe water deficit and growth recovery.

    Directory of Open Access Journals (Sweden)

    Justine Bresson

    Full Text Available Mutualistic bacteria can alter plant phenotypes and confer new abilities to plants. Some plant growth-promoting rhizobacteria (PGPR are known to improve both plant growth and tolerance to multiple stresses, including drought, but reports on their effects on plant survival under severe water deficits are scarce. We investigated the effect of Phyllobacterium brassicacearum STM196 strain, a PGPR isolated from the rhizosphere of oilseed rape, on survival, growth and physiological responses of Arabidopsis thaliana to severe water deficits combining destructive and non-destructive high-throughput phenotyping. Soil inoculation with STM196 greatly increased the survival rate of A. thaliana under several scenarios of severe water deficit. Photosystem II efficiency, assessed at the whole-plant level by high-throughput fluorescence imaging (Fv/Fm, was related to the probability of survival and revealed that STM196 delayed plant mortality. Inoculated surviving plants tolerated more damages to the photosynthetic tissues through a delayed dehydration and a better tolerance to low water status. Importantly, STM196 allowed a better recovery of plant growth after rewatering and stressed plants reached a similar biomass at flowering than non-stressed plants. Our results highlight the importance of plant-bacteria interactions in plant responses to severe drought and provide a new avenue of investigations to improve drought tolerance in agriculture.

  16. LBA-ECO ND-11 Soil Water Pressure and Flow Measurements under Tree Crops

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains information that can be used to examine water fluxes in soils beneath tree crops in an Amazonian agroforest. The data consists of repeated...

  17. LBA-ECO ND-11 Soil Water Pressure and Flow Measurements under Tree Crops

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains information that can be used to examine water fluxes in soils beneath tree crops in an Amazonian agroforest. The data consists of...

  18. Response of antioxidant system of tomato to water deficit stress and its interaction with ascorbic acid

    Directory of Open Access Journals (Sweden)

    Fatemeh Daneshmand

    2014-03-01

    Full Text Available Environmental stresses including water deficit stress may produce oxidants such as reactive oxygen species that damage the membrane structure in plants. Among the antioxidants, ascorbic acid has a critical role in the cell and scavenges reactive oxygen species. In this research, effects of ascorbic acid at two levels (0 and 10 mM and water deficit stress based on 3 levels of field capacity (100, 60 and 30% were studied in tomato plants. Both levels of stress increased lipid peroxidation, reduced the amount of ascorbic acid and glutathione and increased the activity of enzymes superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase and reduced the growth parameters. Ascorbic acid treatment, reduced lipid peroxidation, increased ascorbic acid and glutathione levels and decreased the activity of superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase and guaiacol peroxidase and positive effects of ascorbic acid treatment appeared to improve the plant growth parameters.

  19. Exploiting water versus tolerating drought: water-use strategies of trees in a secondary successional tropical dry forest

    Science.gov (United States)

    Fernando Pineda-García; Horacio Paz; Frederick C. Meinzer; Guillermo Angeles; Guillermo Goldstein

    2015-01-01

    In seasonal plant communities where water availability changes dramatically both between and within seasons, understanding the mechanisms that enable plants to exploit water pulses and to survive drought periods is crucial. By measuring rates of physiological processes, we examined the trade-off between water exploitation and drought tolerance among seedlings of trees...

  20. Single-base methylome analysis reveals dynamic epigenomic differences associated with water deficit in apple.

    Science.gov (United States)

    Xu, Jidi; Zhou, Shasha; Gong, Xiaoqing; Song, Yi; van Nocker, Steve; Ma, Fengwang; Guan, Qingmei

    2018-02-01

    Cytosine methylation is an essential feature of epigenetic regulation and is involved in various biological processes. Although cytosine methylation has been analysed at the genomic scale for several plant species, there is a general lack of understanding of the dynamics of global and genic DNA methylation in plants growing in environments challenged with biotic and abiotic stresses. In this study, we mapped cytosine methylation at single-base resolution in the genome of commercial apple (Malus x domestica), and analysed changes in methylation patterns associated with water deficit in representative drought-sensitive and drought-tolerant cultivars. We found that the apple genome exhibits ~54%, ~38% and ~8.5% methylation at CG, CHG and CHH sequence contexts, respectively. We additionally documented changes in gene expression associated with water deficit in an attempt to link methylation and gene expression changes. Global methylation and transcription analysis revealed that promoter-unmethylated genes showed higher expression levels than promoter-methylated genes. Gene body methylation appears to be positively correlated with gene expression. Water deficit stress was associated with changes in methylation at a multitude of genes, including those encoding transcription factors (TFs) and transposable elements (TEs). These results present a methylome map of the apple genome and reveal widespread DNA methylation alterations in response to water deficit stress. These data will be helpful for understanding potential linkages between DNA methylation and gene expression in plants growing in natural environments and challenged with abiotic and biotic stresses. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Changes in growth rate, root morphology and water use efficiency of potted Callistemon citrinus plants in response to different levels of water deficit

    OpenAIRE

    Álvarez Martín, Sara; Sánchez-Blanco, María Jesús

    2013-01-01

    Callistemon is widely used as a flowering shrub in gardening and landscaping in the Mediterranean area. However, prolonged or severe water stress may alter its physiological and morphological behaviour. Callistemon citrinus plants were grown in nursery conditions and subjected to three irrigation treatments: a control (watered to container capacity) and two water deficit treatments of 50 and 25% of the amount of water supplied in the control treatment (moderate and severe deficit irrigation, ...

  2. Effect of water deficit on water use efficiency of canola (Brassica napus L. cultivars in Mashhad condition

    Directory of Open Access Journals (Sweden)

    S.H. Mousavi

    2016-04-01

    Full Text Available Water deficit is a major factor influencing yield of canola (Brassica napus L. seed yield and oil content. A field experiment was conducted during 2010 growing season in the Agriculture Research Station of Torogh, Mashhad, Iran to evaluate responses of canola cultivars to limited water. Experimental design was RCBD pattern with three replications. Treatments were two irrigation regimes (based on irrigation after 120 mm evaporation on class A pan for stress treatments and 80 mm evaporation for non stress treatments and six rapeseed cultivars(hyola 401, Hyola 330, Parkland, Goldrush, BP18 and landrace. Results showed that water use efficiency was significantly affected by drought stress. Average of water use efficiency at all cultivars in stress treatments was 6.6 Kg per m3 water by 3412.3 m3 water used and 4.5 Kg per m3 water by 4612.3 m3 water used in non stress treatments. The highest and the lowest water use efficiency observed in Hyola 401 and Goldrush by 7.4 and 2.6 kilograms per m3 water in drought stress treatment, respectively. In addition to the ability of oil production by rapeseed cultivars under drought stress was affected and became less in drought stress. Hyola 401 had the highest oil content by 0.28 kg oil per m3 water in non stress and BP.18 had the lowest oil content 0.06 kg oil per m3 water in stress treatment. Results showed that water deficit can affect oil content significantly.

  3. The effects of the recent minimum temperature and water deficit increases on Pinus pinaster wood radial growth and density in southern Portugal.

    Directory of Open Access Journals (Sweden)

    Cathy Béatrice Kurz Besson

    2016-08-01

    Full Text Available Western Iberia has recently shown increasing frequency of drought conditions coupled with heatwave events, leading to exacerbated limiting climatic conditions for plant growth. It is not clear to what extent wood growth and density of agroforestry species have suffered from such changes or recent extreme climate events.To address this question, tree-ring width and density chronologies were built for a P. pinaster stand in southern Portugal and correlated with climate variables, including the minimum, mean and maximum temperatures and the number of cold days. Monthly and maximum daily precipitations were also analyzed as well as dry spells. The drought effect was assessed using the standardized precipitation-evapotranspiration (SPEI multi-scalar drought index, between 1 to 24-months. The climate-growth/density relationships were evaluated for the period 1958-2011.We show that both wood radial growth and density highly benefit from the strong decay of cold days and the increase of minimum temperature. Yet the benefits are hindered by long-term water deficit, which results in different levels of impact on wood radial growth and density. Despite of the intensification of long-term water deficit, tree-ring width appears to benefit from the minimum temperature increase, whereas the effects of long-term droughts significantly prevail on tree-ring density. Our results further highlight the dependency of the species on deep water sources after the juvenile stage. The impact of climate changes on long-term droughts and their repercussion on the shallow groundwater table and P. pinaster’s vulnerability are also discussed. This work provides relevant information for forest management in the semi-arid area of the Alentejo region of Portugal. It should ease the elaboration of mitigation strategies to assure P. pinaster’s production capacity and quality in response to more arid conditions in the near future in the region.

  4. Tree level hydrodynamic approach for resolving aboveground water storage and stomatal conductance and modeling the effects of tree hydraulic strategy

    Science.gov (United States)

    Mirfenderesgi, Golnazalsadat; Bohrer, Gil; Matheny, Ashley M.; Fatichi, Simone; de Moraes Frasson, Renato Prata; Schäfer, Karina V. R.

    2016-07-01

    The finite difference ecosystem-scale tree crown hydrodynamics model version 2 (FETCH2) is a tree-scale hydrodynamic model of transpiration. The FETCH2 model employs a finite difference numerical methodology and a simplified single-beam conduit system to explicitly resolve xylem water potentials throughout the vertical extent of a tree. Empirical equations relate water potential within the stem to stomatal conductance of the leaves at each height throughout the crown. While highly simplified, this approach brings additional realism to the simulation of transpiration by linking stomatal responses to stem water potential rather than directly to soil moisture, as is currently the case in the majority of land surface models. FETCH2 accounts for plant hydraulic traits, such as the degree of anisohydric/isohydric response of stomata, maximal xylem conductivity, vertical distribution of leaf area, and maximal and minimal xylem water content. We used FETCH2 along with sap flow and eddy covariance data sets collected from a mixed plot of two genera (oak/pine) in Silas Little Experimental Forest, NJ, USA, to conduct an analysis of the intergeneric variation of hydraulic strategies and their effects on diurnal and seasonal transpiration dynamics. We define these strategies through the parameters that describe the genus level transpiration and xylem conductivity responses to changes in stem water potential. Our evaluation revealed that FETCH2 considerably improved the simulation of ecosystem transpiration and latent heat flux in comparison to more conventional models. A virtual experiment showed that the model was able to capture the effect of hydraulic strategies such as isohydric/anisohydric behavior on stomatal conductance under different soil-water availability conditions.

  5. Subtractive libraries for prospecting differentially expressed genes in the soybean under water deficit.

    Science.gov (United States)

    Rodrigues, Fabiana Aparecida; Marcolino-Gomes, Juliana; de Fátima Corrêa Carvalho, Josirlei; do Nascimento, Leandro Costa; Neumaier, Norman; Farias, José Renato Bouças; Carazzolle, Marcelo Falsarella; Marcelino, Francismar Corrêa; Nepomuceno, Alexandre Lima

    2012-06-01

    Soybean has a wide range of applications in the industry and, due to its crop potential, its improvement is widely desirable. During drought conditions, soybean crops suffer significant losses in productivity. Therefore, understanding the responses of the soybean under this stress is an effective way of targeting crop improvement techniques. In this study, we employed the Suppressive Subtractive Hybridization (SSH) technique to investigate differentially expressed genes under water deficit conditions. Embrapa 48 and BR 16 soybean lines, known as drought-tolerant and -sensitive, respectively, were grown hydroponically and subjected to different short-term periods of stress by withholding the nutrient solution. Using this approach, we have identified genes expressed during the early response to water deficit in roots and leaves. These genes were compared among the lines to assess probable differences in the plant transcriptomes. In general, similar biochemical processes were predominant in both cultivars; however, there were more considerable differences between roots and leaves of Embrapa 48. Moreover, we present here a fast, clean and straightforward method to obtain drought-stressed root tissues and a large enriched collection of transcripts expressed by soybean plants under water deficit that can be useful for further studies towards the understanding of plant responses to stress.

  6. ABA-mediated responses to water deficit separate grapevine genotypes by their genetic background.

    Science.gov (United States)

    Rossdeutsch, Landry; Edwards, Everard; Cookson, Sarah J; Barrieu, François; Gambetta, Gregory A; Delrot, Serge; Ollat, Nathalie

    2016-04-18

    ABA-mediated processes are involved in plant responses to water deficit, especially the control of stomatal opening. However in grapevine it is not known if these processes participate in the phenotypic variation in drought adaptation existing between genotypes. To elucidate this question, the response to short-term water-deficit was analysed in roots and shoots of nine Vitis genotypes differing in their drought adaptation in the field. The transcript abundance of 12 genes involved in ABA biosynthesis, catabolism, and signalling were monitored, together with physiological and metabolic parameters related to ABA and its role in controlling plant transpiration. Although transpiration and ABA responses were well-conserved among the genotypes, multifactorial analyses separated Vitis vinifera varieties and V. berlandieri x V. rupestris hybrids (all considered drought tolerant) from the other genotypes studied. Generally, V. vinifera varieties, followed by V. berlandieri x V. rupestris hybrids, displayed more pronounced responses to water-deficit in comparison to the other genotypes. However, changes in transcript abundance in roots were more pronounced for Vitis hybrids than V. vinifera genotypes. Changes in the expression of the cornerstone ABA biosynthetic gene VviNCED1, and the ABA transcriptional regulator VviABF1, were associated with the response of V. vinifera genotypes, while changes in VviNCED2 abundance were associated with the response of other Vitis genotypes. In contrast, the ABA RCAR receptors were not identified as key components of the genotypic variability of water-deficit responses. Interestingly, the expression of VviSnRK2.6 (an AtOST1 ortholog) was constitutively lower in roots and leaves of V. vinifera genotypes and higher in roots of V. berlandieri x V. rupestris hybrids. This study highlights that Vitis genotypes exhibiting different levels of drought adaptation differ in key steps involved in ABA metabolism and signalling; both under well-watered

  7. The watering of tall trees--embolization and recovery.

    Science.gov (United States)

    Gouin, Henri

    2015-03-21

    We can propound a thermo-mechanical understanding of the ascent of sap to the top of tall trees thanks to a comparison between experiments associated with the cohesion-tension theory and the disjoining pressure concept for liquid thin-films. When a segment of xylem is tight-filled with crude sap, the liquid pressure can be negative although the pressure in embolized vessels remains positive. Examples are given that illustrate how embolized vessels can be refilled and why the ascent of sap is possible even in the tallest trees avoiding the problem due to cavitation. However, the maximum height of trees is limited by the stability domain of liquid thin-films. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effect of water deficit on morphological and physiological parameters of Carum copticum

    Directory of Open Access Journals (Sweden)

    Shahla Najafi

    2014-12-01

    Full Text Available Ajwan (Carum Copticum L. is an important plant in Apiaceae family and has many medical uses. In this research, the effects of water deficit stress on growth, yield, compatible metabolite accumulations (proline and carbohydrates and plant ingredients were studied under controlled conditions in a greenhouse. Water deficit levels included mild stress (90% field capacity, medium stress (70% field capacity and severe stress (50% field capacity . In 50% field capacity, the plant didn't reach to seeding stage. Also, In this study, seed essence of plants under water stress, levels of 70 and 90% field capacity, was obtained by distillation with water and chemical compounds of essence were analyzed by GC/MS method .The statistical results showed significant effects of water stress on growth parameters, seed yield, proline accumulation, carbohydrate accumulation, oil yield and essential oil percentage. The increase of water stress decreased plant height, number of lateral branches, dry weight and seed yield. However, oil yield, oil percentage, proline and carbohydrate contents increased. The highest amounts of proline and carbohydrate at the 50% of field capacity (high stress and also the maximum essential oil yield and percentage of essential oil at 70% field capacity were observed. Twenty-one chemical compounds were identified in both of the essences of Carum Copticum, and thymol, gamatherpinen and parasimen in each treatment were changed.

  9. REUSE OF TREATED WASTEWATER IN AGRICULTURE: SOLVING WATER DEFICIT PROBLEMS IN ARID AREAS (REVIEW

    Directory of Open Access Journals (Sweden)

    Faissal AZIZ

    2014-12-01

    Full Text Available In the arid and semiarid areas, the availability and the management of irrigation water have become priorities of great importance. The successive years of drought, induced by climate change and population growth, increasingly reduced the amount of water reserved for agriculture. Consequently, many countries have included wastewater reuse as an important dimension of water resources planning. In the more arid areas wastewater is used in agriculture, releasing high resource of water supplies. In this context, the present work is a review focusing the reuse of treated wastewater in agriculture as an important strategy for solving water deficit problems in arid areas. Much information concerning the wastewater reuse in different regions of the world and in Morocco, the different wastewater treatment technologies existing in Morocco were discussed. The review focused also the fertilizing potential of wastewater in agriculture, the role of nutrients and their concentrations in wastewater and their advantages effects on plant growth and yield.

  10. Spring water deficit and soil conditions matter more than seed origin and summer drought for the establishment of temperate conifers.

    Science.gov (United States)

    Moser, Barbara; Walthert, Lorenz; Metslaid, Marek; Wasem, Ulrich; Wohlgemuth, Thomas

    2017-02-01

    In anticipation of more severe summer droughts, forestry in temperate Europe is searching for drought-resistant ecotypes of native tree species that might maintain ecosystem services in the future. We investigated how spring precipitation and soil conditions interact with summer drought and affect the establishment of conifer seedlings from different climatic origin. Emergence, establishment and subsequent performance of seedlings originating from autochthonous, Central Alpine, continental Eastern European, and Mediterranean Pinus sylvestris and Picea abies populations were studied in the dry Alpine Rhine valley, Switzerland, at three sites with differing soil water holding capacities and in 3 years with contrasting weather conditions. In addition to this natural inter-annual variation, precipitation was manipulated within sites with throughfall reduction roofs. Seedling establishment and growth were principally affected by the spring weather in the year of emergence. In years with average to positive spring water balance, seedlings grown at the site with the highest water holding capacity had 2-5 times more aboveground biomass than seedlings grown at sites with less favourable soils. Effects of seed origin were marginal and only detectable at the drier sites: contrary to our expectations, seedlings from the Central Alpine Rhone valley, where the climatic spring water deficit is large, outperformed those from the Mediterranean. Consequently, plantation of non-native populations from dryer origin will mitigate the effects of increased summer drought at driest sites only, while the inter-annual variability of spring precipitation will continue to enable temperate conifers to regenerate on a wide range of forest soils independent of seed origin.

  11. Condensation onto the skin as a means for water gain by tree frogs in tropical Australia.

    Science.gov (United States)

    Tracy, Christopher R; Laurence, Nathalie; Christian, Keith A

    2011-10-01

    Green tree frogs, Litoria caerulea, in the wet-dry tropics of northern Australia remain active during the dry season with apparently no available water and temperatures that approach their lower critical temperature. We hypothesized that this surprising activity might be because frogs that are cooled during nighttime activity gain water from condensation by returning to a warm, humid tree hollow. We measured the mass gained when a cool frog moved into either a natural or an artificial hollow. In both hollows, water condensed on cool L. caerulea, resulting in water gains of up to 0.93% of body mass. We estimated that the water gained was more than the water that would be lost to evaporation during activity. The use of condensation as a means for water gain may be a significant source of water uptake for species like L. caerulea that occur in areas where free water is unavailable over extended periods.

  12. Water economy of neotropical savanna trees: six paradigms revisited.

    Science.gov (United States)

    Guillermo Goldstein; Fredrick C. Meinzer; Sandra J. Bucci

    2008-01-01

    Biologists have long been puzzled by the striking morphological and anatomical characteristics of Neotropical savanna trees which have large scleromorphic leaves, allocate more than half of their total biomass to belowground structures and produce new leaves during the peak of the dry season. Based on results of ongoing interdisciplinary projects in the savannas of...

  13. The phenology pattern of rubber trees in plantation and its impacts on rubber tree structure, water and carbon cycles

    Science.gov (United States)

    Liu, W.; Giambelluca, T. W.; Mudd, R. G.

    2012-12-01

    Commercial rubber (Hevea Brasiliensis) is originally native to the Amazon rainforest and it has become one of the important commercial crops in Mainland Southeast Asia. Similarly to some trees species in Amazon but quite distinctly from other native forests in Southeast Asia, rubber tree sheds its leaves in the middle of dry season and flushes new leaves before the onset of the wet season. Moreover, the mountane mainland Southeast Asia is heavily influenced by the monsoon climate which has most the precipitation in the wet season while almost no rainfall in the dry season. It is believed that the phenology pattern of rubber interacted with local climate would not only regulate the seasonal rubber plantation structures but also further alter the local energy and water budget. However, it is still lack of solid understandings of how the phenology patterns in terms of the leaf area index (LAI) changes of the rubber tree response to environmental drivers. The study tries to shed lights on the issue from analyses of a various types of in-situ field data combined with 3 years' tower flux measurements collected within the rubber plantations. It concludes that: 1) Both the monthly tree height increment and the monthly biomass accumulation are highly correlated with the LAI changes, which have the low rate of changes in the dry season versus the relative high rate of changes in the wet season; 2) the daily evapotranspiration (ET) of the rubber tree is very sensitive to the daily LAI changes in the dry season (R2 > 0.9); 3) the LAI changes, especially the leaf drops, are majorly determined by the accumulated precipitation in the past three months.

  14. Root-derived bicarbonate assimilation in response to variable water deficit in Camptotheca acuminate seedlings.

    Science.gov (United States)

    Rao, Sen; Wu, Yanyou

    2017-10-01

    Water deficit is one of the key factors that limits the carbon (C) assimilation and productivity of plants. The effect of variable water deficit on recently root-derived bicarbonate assimilation in Camptotheca acuminate seedlings was investigated. Three-month-old seedlings were subjected to three water regimes, well-watered (WW), moderate stress (MS), and severe stress (SS) induced by polyethyleneglycol, in conjunction with relatively high (H) and low (L) natural 13C-abundance of NaHCO3-labeled treatments in hydroponics for 14 days. The δ13C of the newly expanded leaves in H were generally more enriched in heavy isotopes than were those in L, indicative of the involvement of bicarbonate in aboveground tissues. The C isotope fractionation of newly expanded leaves relative to air (∆13Cair-leaves) ranged from 17.78 to 21.78‰ among the treatments. The ∆13Cair-leaves under the MS and SS treatments in H were both more negative than was that in L. A linear regression between Ci/Ca and ∆13Cair-leaves in both L and H were different from the theoretical regression. On the basis of the two end-member mixing model, the proportion of fixed CO2 supplied from bicarbonate contributing to the total photosynthetically inorganic C assimilation were 10.34, 20.05 and 16.60% under the WW, MS, and SS treatments, respectively. These results indicated that the increase in water deficit decreased the atmospheric CO2 gain but triggered a compensatory use of bicarbonate in C. acuminate seedlings.

  15. Interaction of Methanol Spray and Water-Deficit Stress on Photosynthesis and Biochemical Characteristics of Phaseolus vulgaris L. cv. Sadry.

    Science.gov (United States)

    Armand, Nezam; Amiri, Hamzeh; Ismaili, Ahmad

    2016-01-01

    This study was a factorial experiment with a completely randomized design and three replications. The four levels of methanol spraying were used. Spraying was carried out three times during the growing season at 10-day intervals beginning at 4 weeks after sowing. The spraying of solution continued until saturation of droplets on the leaves was achieved. The levels of water-deficit stress applied were nonstress, moderate water stress and severe water stress. The results showed that there was a significant difference (P ≤ 0.05) between the methanol and water-deficit stress treatments for chlorophyll (Chl) a and Chl b, carotenoid, total chlorophyll, net photosynthesis (PN ), intercellular CO2 (Ci ), maximal quantum yield of photosystem II photochemistry (Fv /Fm ), leaf moisture, water use efficiency and relative water content. The application of foliar methanol at all levels of water-deficit stress significantly decreased the catalase activity of the roots. Under all levels of water-deficit stress, the 30% (v/v) methanol treatment significantly decreased peroxidase activity in the roots over that for the control. The results suggest that foliar application of methanol can decrease the negative effects of water-deficit stress on Phaseolus vulgaris L. cv. Sadry. © 2015 The American Society of Photobiology.

  16. Effect of the season on the free phytoprostane content in Cornicabra extra virgin olive oil from deficit-irrigated olive trees.

    Science.gov (United States)

    Collado-González, Jacinta; Pérez-López, David; Memmi, Houssem; Gijón, M Carmen; Medina, Sonia; Durand, Thierry; Guy, Alexandre; Galano, Jean-Marie; Fernández, Diego José; Carro, Fernando; Ferreres, Federico; Torrecillas, Arturo; Gil-Izquierdo, Angel

    2016-03-30

    The effect of regulated deficit irrigation (RDI) on the phytoprostane (PhytoP) content in extra virgin olive (Olea europaea L., cv. Cornicabra) oil (EVOO) was studied. During the 2012 and 2013 seasons, T0 plants were irrigated at 100% ETc, while T1 and T2 plants were irrigated avoiding water deficit during phases I and III of fruit growth and saving water during the non-critical phenological period of pit hardening (phase II), developing a more severe water deficit in T2 plants. In 2013, a fourth treatment (T3) was also performed, which was similar to T2 except that water saving was from the beginning of phase II to 15 days after the end of phase II. 9-F1t -PhytoP, 9-epi-9-F1t -PhytoP, 9-epi-9-D1t -PhytoP, 9-D1t -PhytoP, 16-B1 -PhytoP and 9-L1 -PhytoP were present in Cornicabra EVOO, and their contents increased in the EVOO from RDI plants. Deficit irrigation during pit hardening or for a further period of 2 weeks thereafter to increase irrigation water saving is clearly critical for EVOO composition because of the enhancement of free PhytoPs, which have potential beneficial effects on human health. The response of individual free PhytoPs to changes in plant water status was not as perceptible as expected, preventing their use as biomarkers of water stress. © 2015 Society of Chemical Industry.

  17. The Effect of Water Deficit Imposing Methods on Quantitative and Qualitative Traits of New Potato Cultivar

    Directory of Open Access Journals (Sweden)

    Kh Parvizi

    2016-02-01

    Full Text Available Introduction Water deficiency is the main factor that limits crop production in arid and semiarid regions. Due to limitation in water resources, low efficiency of water in surface irrigation method and irregular rainfall application of sprinkle and triple irrigation methods is inevitable in more regions of Iran. In this respect, it is crucial to employ methods that can improve water use efficiency and do not damage the sustainable production of potato in these regions. Introduction of some potato cultivars that have good capability of yield in deficit irrigation is anopportunity in this case. In previous study new released potato cultivar (Savalan and three other promising clones had more yield and growing potential compared with Agriacultivar. Therefore, it was necessary to evaluate new cultivar (Savalan and promising clones in water deficit irrigation. In this respect, as is expected, if cultivars or clones have more tolerance to water deficit they canbe suitable cultivar candidate and germplasms in water critical water conditions in many regions of Iran. Material and Methods This experiment has been conducted in Agricultural and Natural Resources Research Center of Hamedanin split plot design based on Randomized Complete Block in three replications with two factors, including: 1. Water deficit irrigation treatment, 50, 60, 70, 80, 90 and 100% of regular potato irrigation requirement. 2. Three clones accompanied with Savalan and Sante Cultivars. Irrigation system was tape method. Irrigation treatments were established immediately after cultivation of tubers. Water requirement was calculated through corrected vapotranspiration (ETo determined by Penman-Monteith equation considering 90% water use efficiency. During the growing season, fewgrowing indices including, flowering longevity and harvesting time were recorded along with measurement of dry and fresh root weights. Total yield was measured by selecting randomly of 2 m2in every plot

  18. Reliance on deep soil water in the tree species Argania spinosa.

    Science.gov (United States)

    Zunzunegui, M; Boutaleb, S; Díaz Barradas, M C; Esquivias, M P; Valera, J; Jáuregui, J; Tagma, T; Ain-Lhout, F

    2017-12-07

    In South-western Morocco, water scarcity and high temperature are the main factors determining species survival. Argania spinosa (L.) Skeels is a tree species, endemic to Morocco, which is suffering from ongoing habitat shrinkage. Argan trees play essential local ecological and economic roles: protecting soils from erosion, shading different types of crops, helping maintain soil fertility and, even more importantly, its seeds are used by the local population for oil production, with valuable nutritional, medicinal and cosmetic purposes. The main objective of this study was to identify the sources of water used by this species and to assess the effect of water availability on the photosynthetic rate and stem water potential in two populations: one growing on the coast and a second one 10 km inland. Stem water potential, photosynthetic rate and xylem water isotopic composition (δ18O) were seasonally monitored during 2 years. Trees from both populations showed a similar strategy in the use of the available water sources, which was strongly dependent on deep soil water throughout the year. Nevertheless, during the wet season or under low precipitation a more complex water uptake pattern was found with a mixture of water sources, including precipitation and soil at different depths. No evidence was found of the use of either groundwater or atmospheric water in this species. Despite the similar water-use strategy, the results indicate that Argania trees from the inland population explored deeper layers than coastal ones as suggested by more depleted δ18O values recorded in the inland trees and better photosynthetic performance, hence suggesting that the coastal population of A. spinosa could be subjected to higher stress. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Vine Water Deficit Impacts Aging Bouquet in Fine Red Bordeaux Wine.

    Science.gov (United States)

    Picard, Magali; van Leeuwen, Cornelis; Guyon, François; Gaillard, Laetitia; de Revel, Gilles; Marchand, Stéphanie

    2017-01-01

    The aim of this study was to investigate the influence of vine water status on bouquet typicality, revealed after aging, and the perception of three aromatic notes (mint, truffle, and undergrowth) in bottled fine red Bordeaux wines. To address the issue of the role of vine water deficit in the overall quality of fine aged wines, a large set of wines from four Bordeaux appellations were subjected to sensory analysis. As vine water status can be characterized by carbon isotope discrimination (δ13C), this ratio was quantified for each wine studied. Statistical analyses combining δ13C and sensory data highlighted that δ13C-values discriminated effectively between the most- and least-typical wines. In addition, Principal Component Analysis (PCA) revealed correlations between δ13C-values and truffle, undergrowth, and mint aromatic notes, three characteristics of the red Bordeaux wine aging bouquet. These correlations were confirmed to be significant using a Spearman statistical test. This study highlighted for the first time that vine water deficit positively relates to the perception of aging bouquet typicality, as well as the expression of its key aromatic nuances.

  20. Vine water deficit impacts aging bouquet in fine red Bordeaux wine

    Science.gov (United States)

    Picard, Magali; van Leeuwen, Cornelis; Guyon, François; Gaillard, Laetitia; de Revel, Gilles; Marchand, Stéphanie

    2017-08-01

    The aim of this study was to investigate the influence of vine water status on bouquet typicality, revealed after aging, and the perception of three aromatic notes (mint, truffle, and undergrowth) in bottled fine red Bordeaux wines. To address the issue of the role of vine water deficit in the overall quality of fine aged wines, a large set of wines from four Bordeaux appellations were subjected to sensory analysis. As vine water status can be characterized by carbon isotope discrimination (δ13C), this ratio was quantified for each wine studied. Statistical analyses combining δ13C and sensory data highlighted that δ13C values discriminated effectively between the most- and least-typical wines. In addition, Principal Component Analysis revealed correlations between δ13C values and truffle, undergrowth, and mint aromatic notes, three characteristics of the red Bordeaux wine aging bouquet. These correlations were confirmed to be significant using a Spearman statistical test. This study highlighted for the first time that vine water deficit positively relates to the perception of aging bouquet typicality, as well as the expression of its key aromatic nuances.

  1. Effects of water vapor density on cutaneous resistance to evaporative water loss and body temperature in green tree frogs (Hyla cinerea).

    Science.gov (United States)

    Wygoda, Mark L; Kersten, Constance A

    2013-01-01

    Increased cutaneous resistance to evaporative water loss (Rc) in tree frogs results in decreased water loss rate and increased body temperature. We examined sensitivity of Rc to water vapor density (WVD) in Hyla cinerea by exposing individual frogs and agar models to four different WVD environments and measuring cutaneous evaporative water loss rate and body temperature simultaneously using a gravimetric wind tunnel measuring system. We found that water loss rate varied inversely and body temperature directly with WVD but that models were affected to a greater extent than were animals. Mean Rc was significantly different between the highest WVD environment and each of the three drier environments but did not differ among the drier environments, indicating that Rc initially increases and then reaches a plateau in response to decreasing WVD. Rc was equivalent when calculated using either WVD difference or WVD deficit as the driving force for evaporation. We also directly observed secretions from cutaneous glands while measuring body temperature and tested secretions and skin samples for the presence of lipids. We found that irregular transient body temperature depressions observed during wind tunnel trials occur due to evaporative cooling from intermittent skin secretions containing lipids, although we were unable to identify lipid-secreting glands.

  2. Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

    Directory of Open Access Journals (Sweden)

    Deborah M G Apgaua

    Full Text Available Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees. We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

  3. Functional Traits and Water Transport Strategies in Lowland Tropical Rainforest Trees.

    Science.gov (United States)

    Apgaua, Deborah M G; Ishida, Françoise Y; Tng, David Y P; Laidlaw, Melinda J; Santos, Rubens M; Rumman, Rizwana; Eamus, Derek; Holtum, Joseph A M; Laurance, Susan G W

    2015-01-01

    Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the hydraulic variability in trees in a lowland tropical rainforest in north-eastern Australia. We studied eight tree species representing broad plant functional groups (one palm and seven eudicot mature-phase, and early-successional trees). We characterised the species' hydraulic system through maximum rates of volumetric sap flow and velocities using the heat ratio method, and measured rates of tree growth and several stem, vessel, and leaf traits. Sap flow measures exhibited limited variability across species, although early-successional species and palms had high mean sap velocities relative to most mature-phase species. Stem, vessel, and leaf traits were poor predictors of sap flow measures. However, these traits exhibited different associations in multivariate analysis, revealing gradients in some traits across species and alternative hydraulic strategies in others. Trait differences across and within tree functional groups reflect variation in water transport and drought resistance strategies. These varying strategies will help in our understanding of changing species distributions under predicted drought scenarios.

  4. Impacts of mechanical tree felling on development of water tupelo regeneration in the Mobile Delta, Alabama

    Science.gov (United States)

    Emile S. Gardiner; D. Ramsey Russell; John D. Hodges; T. Conner Fristoe

    2000-01-01

    Two water tupelo (Nyssa aquatica L.) stands in the Mobile Delta of Alabama were selected to test the hypothesis that mechanized felling does not reduce establishment and growth of natural water tupelo regeneration relative to traditional tree felling with chainsaws. To test the hypothesis, we established six 2 acre treatment plots in each of two...

  5. Improving of Barley Seedling Growth by Seed Priming Under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Jalal Jalilian

    2014-05-01

    Full Text Available Seed priming was used to reinforcement of barley seedling growth under water deficit stress in a greenhouse condition. Barley seeds were primed with humic acid, Pseudomonas Spp., Marmarin, distilled water (hydropriming and none (as control under four levels of water deficit stress (irrigation at 20 (I1, 40 (I2, 60 (I3 and 80% (I4 field capacity. Results indicated that all measured parameters were decreased with increasing the stress levels, except root length and root-shoot ratio. The highest value of root length (18.42 cm and root-shoot ratio (2.84 was obtained in the I1 irrigation regime. However, I2, I3 and I4 irrigation regimes did not significantly affect on barley seedling traits, but I1 irrigation regime exhibited better growth. Seed priming with Pseudomonas affected root length, root and shoot dry weight, plant height and SPAD, significantly. Seed priming with Marmarin showed best results on SPAD. The maximum (0.37 g/plant shoot dry weight was obtained from I2 irrigation regime with hydropriming treatment. Whereas, the lowest shoot dry weight (0.14 g/plant was observed in I1 irrigation regimes in control condition. Hydropriming shows better response in root length, root and shoot and plant height and was equal with Pseudomonas, so it could be considered as a suitable substitute in organic agricultural systems.

  6. Tree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes.

    Science.gov (United States)

    Brienen, R J W; Gloor, E; Clerici, S; Newton, R; Arppe, L; Boom, A; Bottrell, S; Callaghan, M; Heaton, T; Helama, S; Helle, G; Leng, M J; Mielikäinen, K; Oinonen, M; Timonen, M

    2017-08-18

    Various studies report substantial increases in intrinsic water-use efficiency (W i ), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in W i as trees grow larger. Here we show, by comparing W i across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees' W i . W i doubled or even tripled over a trees' lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred.Intrinsic water-use efficiency (W i ) reconstructions using tree rings often disregard developmental changes in W i as trees age. Here, the authors compare W i across varying tree sizes at a fixed CO2 level and show that ignoring developmental changes impacts conclusions on trees' W i responses to CO2 or climate.

  7. Cell Wall Proteome in the Maize Primary Root Elongation Zone. II. Region-Specific Changes in Water Soluble and Lightly Ionically Bound Proteins under Water Deficit

    National Research Council Canada - National Science Library

    Jinming Zhu; Sophie Alvarez; Ellen L. Marsh; Mary E. LeNoble; In-Jeong Cho; Mayandi Sivaguru; Sixue Chen; Henry T. Nguyen; Yajun Wu; Daniel P. Schachtman; Robert E. Sharp

    2007-01-01

    Previous work on the adaptation of maize (Zea mays) primary roots to water deficit showed that cell elongation is maintained preferentially toward the apex, and that this response involves modification of cell wall extension properties...

  8. An investigation of the relationship between tree water potential and dielectric constant

    Science.gov (United States)

    Mcdonald, Kyle C.; Zimmermann, Reiner; Way, Jobea; Oren, Ram

    1992-01-01

    An experiment that has been performed to verify the relationship between the dielectric constant of several tree species and their respective water potentials is described. The water potential, xylem flow and dielectric properties of five tree species were continuously monitored while simultaneously manipulating canopy transpiration and water status. An analysis of the data recorded during these manipulations is presented. Results of this analysis demonstrate a clear coincidence of change in dielectric constant and water status. The implication of this relationship for the utilization of remotely sensed data to study canopy water relations is explored. Preliminary backscatter modeling results demonstrate that the changes in dielectric constant that occur as a result of changes in water status are significant enough to be observable with microwave radar.

  9. Low-field nuclear magnetic resonance for the in vivo study of water content in trees

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, Jacob, E-mail: jlyoder@lanl.gov [Inorganic, Isotope and Actinide Chemistry, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Malone, Michael W.; Espy, Michelle A. [Applied Modern Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Sevanto, Sanna [Earth Systems Observations, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-09-15

    Nuclear magnetic resonance (NMR) and magnetic resonance imaging have long been used to study water content in plants. Approaches have been primarily based on systems using large magnetic fields (∼1 T) to obtain NMR signals with good signal-to-noise. This is because the NMR signal scales approximately with the magnetic field strength squared. However, there are also limits to this approach in terms of realistic physiological configuration or those imposed by the size and cost of the magnet. Here we have taken a different approach – keeping the magnetic field low to produce a very light and inexpensive system, suitable for bulk water measurements on trees less than 5 cm in diameter, which could easily be duplicated to measure on many trees or from multiple parts of the same tree. Using this system we have shown sensitivity to water content in trees and their cuttings and observed a diurnal signal variation in tree water content in a greenhouse. We also demonstrate that, with calibration and modeling of the thermal polarization, the system is reliable under significant temperature variation.

  10. Effect of nitrogen and water deficit type on the yield gap between the potential and attainable wheat yield

    Directory of Open Access Journals (Sweden)

    Jiangang Liu

    2015-12-01

    Full Text Available Water deficit and N fertilizer are the two primary limiting factors for wheat yield in the North China plain, the most important winter wheat (Triticum aestivum L. production area in China. Analyzing the yield gap between the potential yield and the attainable yield can quantify the potential for increasing wheat production and exploring the limiting factors to yield gap in the high-yielding farming region of North China Plain. The Decision Support System for Agrotechnology Transfer (DSSAT model was used to identify methods to increase the grain yield and decrease the gap. In order to explore the impact of N and cultivars on wheat yield in the different drought types, the climate conditions during 1981 to 2011 growing seasons was categorized into low, moderate, and severe water deficit classes according to the anomaly percentage of the water deficit rate during the entire wheat growing season. There are differences (P < 0.0001 in the variations of the potential yields among three cultivars over 30 yr. For all three water deficit types, the more recent cultivars Jimai22 and Shijiazhuang8 had higher yields compared to the older 'Jinan17'. As the N fertilizer rate increased, the yield gap decreased more substantially during the low water deficit years because of the significant increase in attainable yield. Overall, the yield gaps were smaller with less water stress. Replacement of cultivars and appropriate N fertilizer application based on the forecasted drought types can narrow the yield gap effectively.

  11. Changes in content of free, conjugated and bound polyamines and osmotic adjustment in adaptation of vetiver grass to water deficit.

    Science.gov (United States)

    Zhou, Qiang; Yu, Bingjun

    2010-06-01

    Osmotic adjustment and alteration of polyamines (PAs) have been suggested to play roles in plant adaptation to water deficit/drought stress. In this study, the changes in cell intactness, photosynthesis, compatible solutes and PAs [including putrescine (Put), spermidine (Spd) and spermine (Spm) each in free, conjugated and bound forms] were investigated in leaves of vetiver grass exposed to different intensity of water deficit stress and subsequent rewatering. The results showed that, when vetiver grass was exposed to the moderate (20% and 40% PEG-6000 solutions) and severe (60% PEG solution) water deficit for 6days, the plant injury degree (expressed as the parameters of plant growth, cell membrane integrity, water relations and photosynthesis) increased and contents of free and conjugated Put decreased with the rise of PEG concentration. Under the moderate water deficit, the plants could survive by the reduced osmotic potential (psi(s)), increased free and conjugated Spd and Spm in leaves. After subsequent rewatering, the osmotic balance was re-established, most of the above investigated physiological parameters were fully or partly recovered to the control levels. However, it was not the case for the severely-stressed and rewatering plants. It indicates that, vetiver grass can cope well with the moderate water deficit/drought stress by using the strategies of osmotic adjustment and maintenance of total contents of free, conjugated and bound PAs in leaves.

  12. WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO

    Directory of Open Access Journals (Sweden)

    Mohamed FARISSI

    2014-06-01

    Full Text Available The present study focused the effect of water deficit on agronomic potential and some traits related to forage quality in plants of Moroccan Alfalfa (Medicago sativa L. populations (Taf 1, Taf 2, Dem and Tata originated from Oasis and High Atlas of Morocco and an introduced variety from Australia (Siriver. The experiment was conducted under field conditions in experimental station of INRA-Marrakech and under two irrigation treatments. The first treatment was normal irrigation, providing an amount of water corresponding to the potential evapo-transpiration of the crop, and the second treatment was water deficit stress (one irrigation per cut. For each treatment, the experiment was conducted as a split plot based on a randomized complete block design with four replications. The plants were measured and analyzed over three cuts. Some agronomic traits as, plant height, fresh and dry forage yields were measured. The forage quality was evaluated by leaf:stem ratio and the contents of plants in proteins and nitrogen. The results indicated that the water deficit has negatively affected the plant height and forage yield. The decrease in leaf:stem ratio was observed under water deficit conditions. However, the proteins and nitrogen contents were unaffected. The behavior of tested alfalfa genotypes was significantly different. The Moroccan alfalfa populations were more adapted to water deficit conditions comparatively to Siriver variety and the Tata population was the most adapted one.

  13. Effects of elevated CO2 concentration and water deficit on fructan metabolism in Viguiera discolor Baker.

    Science.gov (United States)

    Oliveira, V F; Silva, E A; Zaidan, L B P; Carvalho, M A M

    2013-05-01

    Elevated [CO2 ] is suggested to mitigate the negative effects of water stress in plants; however responses vary among species. Fructans are recognised as protective compounds against drought and other stresses, as well as having a role as reserve carbohydrates. We analysed the combined effects of elevated [CO2 ] and water deficit on fructan metabolism in the Cerrado species Viguiera discolor Baker. Plants were cultivated for 18 days in open-top chambers (OTC) under ambient (∼380 ppm), and high (∼760 ppm) [CO2 ]. In each OTC, plants were submitted to three treatments: (i) daily watering (control), (ii) withholding water (WS) for 18 days and (iii) re-watering (RW) on day 11. Analyses were performed at time 0 and days 5, 8, 11, 15 and 18. High [CO2 ] increased photosynthesis in control plants and increased water use efficiency in WS plants. The decline in soil water content was more distinct in WS 760 (WS under 760 ppm), although the leaf and tuberous root water status was similar to WS 380 plants (WS under 380 ppm). Regarding fructan active enzymes, 1-SST activity decreased in WS plants in both CO2 concentrations, a result consistent with the decline in photosynthesis and, consequently, in substrate availability. Under WS and both [CO2 ] treatments, 1-FFT and 1-FEH seemed to act in combination to generate osmotically active compounds and thus overcome water deficit. The proportion of hexoses to sucrose, 1-kestose and nystose (SKN) was higher in WS plants. In WS 760, this increase was higher than in WS 380, and was not accompanied by decreases in SKN at the beginning of the treatment, as observed in WS 380 plants. These results suggest that the higher [CO2 ] in the atmosphere contributed to maintain, for a longer period, the pool of hexoses and of low DP fructans, favouring the maintenance of the water status and plant survival under drought. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. Climate change-induced water stress suppresses the regeneration of the critically endangered forest tree Nyssa yunnanensis.

    Science.gov (United States)

    Zhang, Shanshan; Kang, Hongmei; Yang, Wenzhong

    2017-01-01

    Climatic change-induced water stress has been found to threaten the viability of trees, especially endangered species, through inhibiting their recruitment. Nyssa yunnanensis, a plant species with extremely small populations (PSESP), consists of only two small populations of eight mature individuals remaining in southwestern China. In order to determine the barriers to regeneration, both in situ and laboratory experiments were performed to examine the critical factors hindering seed germination and seedling establishment. The results of in situ field experiments demonstrated that soil water potentials lower than -5.40 MPa (experienced in December) had significantly inhibitory effects on seedling survival, and all seedlings perished at a soil water potential of -5.60 MPa (January). Laboratory experiments verified that N. yunnanensis seedlings could not survive at a 20% PEG 6000 concentration (-5.34 MPa) or 1/5 water-holding capacity (WHC; -5.64 MPa), and seed germination was inhibited in the field from September (-1.10 MPa) to November (-4.30 MPa). Our results suggested that soil water potentials between -5.34 and -5.64 MPa constituted the range of soil water potentials in which N. yunnanensis seedlings could not survive. In addition to water deficit, intensified autotoxicity, which is concentration-dependent, resulted in lower seed germination and seedling survival. Thus, seed establishment was probably simultaneously impacted by water deficit and aggravated autotoxicity. Meteorological records from the natural distribution areas of N. yunnanensis indicated that mean annual rainfall and relative humidity have declined by 21.7% and 6.3% respectively over past 55 years, while the temperature has increased by 6.0%. Climate change-induced drought, along with a poor resistance and adaptability to drought stress, has severely impacted the natural regeneration of N. yunnanensis. In conclusion, climate change-induced drought has been implicated as a regulating factor in

  15. Estimating Runoff and Soil Moisture Deficit in Guinea Savannah Region of Nigeria using Water Balance Method

    Directory of Open Access Journals (Sweden)

    A. R. Adesiji

    2012-12-01

    Full Text Available The estimation of runoff and soil moisture deficit in Guinea Savannah region using semi arid model based on soil water balance technique (SAMBA was carried out. The input to the SAMBA model are daily rainfall, daily evapotranspiration, type and date of planting of crop, and soil parameters. The estimated runoff was validated with field measurement taken in a 67.23 ha catchment in the study area. The annual rainfall for the year under study (2009 is 1356.2 mm, the estimated annual evapotranspiration. runoff and recharge are 638mm, 132.93mm, and 447.8mm respectively. Recharge was experienced 23 days after a significant depth of rainfall was recorded. For the crop growth in the catchment, the soil was cropped with a pepper and the growth monitored from the planting to the harvesting. The crop enjoyed so much moisture throughout the growing period as Total Available Water in the soil is greater than Soil Moisture Deficit (TAW>SMD. The model results show that the larger percentage of the total annual rainfall was lost to evaporation and recharge during the growing season. The low runoff and high recharge are attributed to soil characteristics of the area and moderate terrain of the study area.

  16. Transcriptomics analyses of soybean leaf and root samples during water-deficit

    Directory of Open Access Journals (Sweden)

    Prateek Tripathi

    2015-09-01

    Full Text Available Drought being a major challenge for crop productivity and yield affects multigenic and quantitative traits. It is also well documented that water stress shows a cross talk with other abiotic stresses such as high temperature and high light intensities (Tripathi et al., 2013 [1]. In this report, we documented the details of the methods and quality controls used and considered in our time course-based transcriptome profile of soybean plants under water deficit conditions using microarray technology. The findings of this study are recently published by the Rushton lab in BMC Genomics for a comparative study of tobacco and Soybean (Rabara et al., 2015 [2]. The raw microarray data set is deposited in GEO database with accession number GSE49537.

  17. Transcriptomics analyses of soybean leaf and root samples during water-deficit.

    Science.gov (United States)

    Tripathi, Prateek; Rabara, Roel C; Shen, Qingxi J; Rushton, Paul J

    2015-09-01

    Drought being a major challenge for crop productivity and yield affects multigenic and quantitative traits. It is also well documented that water stress shows a cross talk with other abiotic stresses such as high temperature and high light intensities (Tripathi et al., 2013) [1]. In this report, we documented the details of the methods and quality controls used and considered in our time course-based transcriptome profile of soybean plants under water deficit conditions using microarray technology. The findings of this study are recently published by the Rushton lab in BMC Genomics for a comparative study of tobacco and Soybean (Rabara et al., 2015) [2]. The raw microarray data set is deposited in GEO database with accession number GSE49537.

  18. Monsoon Season Moisture Deficit Limits Growth in Co-Occurring Alpine Shrub (Cassiope fastigata) and Tree (Abies spectabilis) Species in the Central Himalayas, Nepal

    Science.gov (United States)

    Rayback, S. A.; Shrestha, K. B.; Hofgaard, A.

    2015-12-01

    Recent evidence indicates changing climatological conditions in the Nepalese Himalayas including decreasing precipitation, a weakening Indian monsoon and rising temperatures. Trees and shrubs found at treeline are considered to be highly sensitive to climate, but the climatic effects on these ecotone species in the Himalayas are not well understood. Dendrochronological techniques applied to co-occurring shrubs and trees up-and down-slope of treeline extend our understanding of vegetation response at range margins and into tree-less environments. We developed tree-ring width and annual height increment chronologies for Abies spectabilis (Himalayan fir) and the first annual growth increment and annual production of leaves chronologies for Cassiope fastigata (Himalayan heather) at a high elevation site in central Nepal. C. fastigata chronologies showed moisture availability in late pre-monsoon and monsoon seasons of the previous year are critical to stem elongation and leaf production (AGI and previous May-August SPEI-12, r = 0.790; LEAF and previous June-September SPEI-12, r = 0.708) A. spectabilis chronologies were significantly and negatively correlated with monsoon season temperature during the current year (tree-ring width and June mean temperature, r = -0.677; height-increment and Sept maximum temperature, r = -0.605). In addition to both long-term and recent declines in moisture in the Himalayas, moisture deficit may be further exacerbated at high elevation sites via run-off and higher levels of evapotranspiration resulting in growth reductions, dieback and even death of these species. These results highlight that not all mid-latitude, high elevation treelines are limited by temperature as previously thought and that severe drought stress may initiate downslope treeline retraction. Understanding the response of co-occurring tree and shrub species to climate, now and in the future, may help to elucidate the physiological mechanisms controlling local and

  19. Effects of management on aquatic tree-hole communities in temperate forests are mediated by detritus amount and water chemistry.

    Science.gov (United States)

    Gossner, Martin M; Lade, Peggy; Rohland, Anja; Sichardt, Nora; Kahl, Tiemo; Bauhus, Jürgen; Weisser, Wolfgang W; Petermann, Jana S

    2016-01-01

    Arthropod communities in water-filled tree holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. We hypothesized that increasing forest management intensity (ForMI) negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree hole size, detritus amount and changed water chemistry at the tree holes scale. We mapped 910 water-filled tree holes in two regions in Germany and studied 199 tree hole inhabiting arthropod communities. We found that increasing ForMI indeed significantly reduced arthropod abundance and richness in water-filled tree holes. The most important indirect effects of management intensity on tree hole community structure were the reduced amounts of detritus for the tree hole inhabiting organisms and changed water chemistry at the tree hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree holes. However, regional species richness in tree holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management-driven increase in plant diversity at the forest stand scale affected communities of individual tree holes, for example via resource availability for adults. Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water-filled tree holes. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  20. Single-tree water use and water-use efficiencies of selected indigenous and introduced species in the Southern Cape region of South Africa

    CSIR Research Space (South Africa)

    Mapeto, P

    2017-03-01

    Full Text Available indigenous tree species can provide an additional low water-use form of forestry. Single-tree water use and water-use efficiencies of three indigenous species (Ilex mitis, Ocotea bullata and Podocarpus latifolius) and one introduced species (Pinus radiata...

  1. The effect of interspecies interactions and water deficit on spring barley and red clover biomass accumulation at successive growth stages

    Directory of Open Access Journals (Sweden)

    Magdalena Jastrzębska

    2016-12-01

    Full Text Available A pot experiment was conducted in a greenhouse in Olsztyn, Poland, in the period 2010–2012. The aim of the study was to examine whether soil water deficit would change biomass volume and distribution of pure sown spring barley and red clover as well as growth rate during their joint vegetation and mutual interactions. The interactions between spring barley and red clover were of a competitive character, and the cereal was the stronger crop. The strength of this competition increased in time with the growing season. Through most of the growing season, the competition was poorer in water deficit conditions. The impact of clover on barley before the heading stage showed facilitation symptoms. Interspecific competition reduced the rate of barley biomass accumulation and decreased stem and leaf biomass towards the end of the growing season. Intensified translocation of assimilates from the vegetative parts to grain minimized the decrease in spike biomass. Water deficit stress had a more inhibitory effect on the biomass and growth rate of barley than competition, and competition did not exacerbate the adverse influence of water deficit stress on barley. Competition from barley significantly reduced the biomass and biomass accumulation rate of clover. Water deficit stress did not exacerbate barley’s competitive effect on clover, but it strongly inhibited the growth of aboveground biomass in pure-sown clover.

  2. Water stress measurements in fruit trees under different regulated deficit irrigation regimes

    OpenAIRE

    Marsal Vila, Jordi

    1997-01-01

    L'aplicació de Reg Deficitari Controlat (RDC) en parcel·les comercials d'arbres fruiters s'enfronta a unaproblemàtica variada. En primer lloc cal buscar una metodologia fiable que permeti caracteritzar l'estrèsen la planta i en segon lloc, cal valorar quin nivell de dèficit és permisible assolir en un cultiu, demanera que els efectes d'aquest estrès no esdevinguin indesitjables. El treball que es presenta preténaprofundir en el coneixement de les relacions hídriques en arbres fruiters amb la ...

  3. Predicting tree water use and drought tolerance from leaf traits in the Los Angeles urban ecosystem

    Science.gov (United States)

    John, G. P.; Scoffoni, C.; Sack, L.

    2013-12-01

    Urban green space provides a suite of valuable ecosystem services. In semiarid systems, like Los Angeles, trees rely primarily on irrigation water for transpiration. Managers may need to reduce irrigation associated with urban trees given climate change, urban expansion, and the steady decrease in available freshwater. While leaf and whole plant water relations have been extensively studied, we are only now gaining a detailed understanding of diverse leaf anatomical designs, and their use for predicting physiology and water use at landscape scale. For 50 diverse urban species, we quantified leaf anatomical and physiological traits important to tree drought tolerance and water use efficiency including turgor loss point, vein architecture, cellular anatomy, leaf mass per unit area, and petiole and leaf dimensions. We hypothesized detailed relationships to develop models relating leaf functional traits to tree water relations. These models provide key insights regarding the role of anatomical designs in leaf stress tolerance and water use efficiency. Additionally we predicted how traits measured at the leaf level would scale with existing data for individuals at the whole plant level. We tested our predictions by determining correlations between leaf level anatomical traits and drought tolerance. Additionally, we determined correlations between functional traits, physiology and water use, and the climate of origin for the urban species. Leaf level measurements will be valuable for rapid estimation of more difficult to measure whole plant water relations traits important at the landscape scale. The Los Angeles urban ecosystem can serve as a model for other semiarid system and provide more informed system wide water conservation strategies.

  4. Evidence for discontinuous water columns in the xylem conduit of tall birch trees.

    Science.gov (United States)

    Westhoff, M; Zimmermann, D; Schneider, H; Wegner, L H; Gessner, P; Jakob, P; Bamberg, E; Shirley, St; Bentrup, F-W; Zimmermann, U

    2009-05-01

    The continuity of the xylem water columns was studied on 17- to 23-m tall birch trees (trunk diameter about 23 cm; first branching above 10 m) all year round. Fifty-one trees were felled, and 5-cm thick slices or 2-m long boles were taken at regular, relatively short intervals over the entire height of the trees. The filling status of the vessels was determined by (i) xylem sap extraction from trunk and branch pieces (using the gas bubble-based jet-discharge method and centrifugation) and from trunk boles (using gravity discharge); (ii) (1)H nuclear magnetic resonance imaging of slice pieces; (iii) infusion experiments (dye, (86)Rb(+), D(2)O) on intact trees and cut branches; and (iv) xylem pressure measurements. This broad array of techniques disclosed no evidence for continuous water-filled columns, as postulated by the Cohesion-Tension theory, for root to apex directed mass transport. Except in early spring (during the xylem refilling phase) and after extremely heavy rainfall during the vegetation period, cohesive/mobile water was found predominantly at intermediate heights of the trunks but not at the base or towards the top of the tree. Similar results were obtained for branches. Furthermore, upper branches generally contained more cohesive/mobile water than lower branches. The results suggest that water lifting occurs by short-distance (capillary, osmotic and/or transpiration-bound) tension gradients as well as by mobilisation of water in the parenchymatic tissues and the heartwood, and by moisture uptake through lenticels.

  5. Methane Production Explained Largely by Water Content in the Heartwood of Living Trees in Upland Forests

    Science.gov (United States)

    Wang, Zhi-Ping; Han, Shi-Jie; Li, Huan-Long; Deng, Feng-Dan; Zheng, Yan-Hai; Liu, Hai-Feng; Han, Xing-Guo

    2017-10-01

    Most forests worldwide are located in upland landscapes. Previous studies have mainly focused on ground methane (CH4) flux in upland forests, and living tree stem-based CH4 processes and fluxes are thus relatively poorly understood. This study investigated the relationship between CH4 concentration and water content in the heartwood of living trees in midtemperate, warm temperate, and subtropical upland forests and also measured seasonal changes of in situ stem CH4 flux and the CH4 concentration and water content in the heartwood of Populus davidiana Dode in a warm temperate upland forest. We found that approximately 4-13% of tree stems or approximately 8-31% of tree species had a substantial CH4 concentration of ≥10,000 μL L-1 in their heartwood across the three types of upland forests. The heartwood CH4 concentration was related to water content by a power function. A threshold of water content occurred beyond which CH4 was produced at high levels in the heartwood. The CH4 emissions from the breast height stems of P. davidiana ranged from 202.1 to 331.6 μg m-2 h-1 on a stem surface area basis during July-October 2016 and were significantly linearly correlated with the CH4 concentration or water content in the heartwood throughout the experimental period, but the linear correlation was not significant at daily and monthly scales. Temperature was not a limiting factor for CH4 production during July-October 2016, and thus, most of the CH4 production may be explained by water content in the heartwood of living trees in upland forests.

  6. Expression pattern of drought stress marker genes in soybean roots under two water deficit systems

    Directory of Open Access Journals (Sweden)

    Anna Cristina Neves-Borges

    2012-01-01

    Full Text Available The study of tolerance mechanisms for drought stress in soybean is fundamental to the understanding and development of tolerant varieties. Using in silico analysis, four marker genes involved in the classical ABA-dependent and ABA-independent pathways of drought response were identified in the Glycine max genome in the present work. The expression profiles of the marker genes ERD1-like, GmaxRD20A-like, GmaxRD22-like and GmaxRD29B-like were investigated by qPCR in root samples of drought sensitive and tolerant soybean cultivars (BR 16 and Embrapa 48, respectively, submitted to water deficit conditions in hydroponic and pot-based systems. Among the four putative soybean homologs to Arabidopsis genes investigated herein, only GmaxRD29B-like was not regulated by water deficit stress. Distinct expression profiles and different induction levels were observed among the genes, as well as between the two drought-inducing systems. Our results showed contrasting gene expression responses for the GmaxRD20A-like and GmaxRD22-like genes. GmaxRD20A-like was highly induced by continuous drought acclimating conditions, whereas GmaxRD22-like responses decreased after abrupt water deprivation. GmaxERD1-like showed a different expression profile for the cultivars in each system. Conversely, GmaxRD20A-like and GmaxRD22-like genes exhibited similar expression levels in tolerant plants in both systems.

  7. Modelling the spectral response of the desert tree Prosopis tamarugo to water stress

    NARCIS (Netherlands)

    Chávez Oyanadel, R.O.; Clevers, J.G.P.W.; Herold, M.; Ortiz, M.; Acevedo, E.

    2013-01-01

    In this paper, we carried out a laboratory experiment to study changes in canopy reflectance of Tamarugo plants under controlled water stress. Tamarugo (Prosopis tamarugo Phil.) is an endemic and endangered tree species adapted to the hyper-arid conditions of the Atacama Desert, Northern Chile.

  8. Survey of economic trees in fresh water swamp of Calabar | Okon ...

    African Journals Online (AJOL)

    A survey of economic trees namely Elaeis guineensis (oil-palm) and Colocasia esculenta (taro) in fresh water swamp, Calabar was conducted. The survey area located in the vicinity of Cross River University of Technology (CRUTECH), Calabar premises covered an area of 0.5km x 0.2km was divided into five plots (A – E).

  9. Using deficit irrigation with treated wastewater to improve crop water productivity of sweet corn, chickpea, faba bean and quinoa

    Directory of Open Access Journals (Sweden)

    Abdelaziz HIRICH

    2014-07-01

    Full Text Available Several experiments were conducted in the south of Morocco (IAV-CHA, Agadir during two seasons 2010 and 2011 in order to evaluate the effect of deficit irrigation with treated wastewater on several crops (quinoa, sweet corn, faba bean and chickpeas. During the first season (2010 three crops were tested, quinoa, chickpeas and sweet corn applying 6 deficit irrigation treatments during all crop stages alternating 100% of full irrigation as non-stress condition and 50% of full irrigation as water deficit condition applied during vegetative growth, flowering and grain filling stage. For all crops, the highest water productivity and yield were obtained when deficit irrigation was applied during the vegetative growth stage. During the second season (2011 two cultivars of quinoa, faba bean and sweet corn have been cultivated applying 6 deficit irrigation treatments (rainfed, 0, 25, 50, 75 and 100% of full irrigation only during the vegetative growth stage, while in the rest of crop cycle full irrigation was provided except for rainfed treatment. For quinoa and faba bean, treatment receiving 50% of full irrigation during vegetative growth stage recorded the highest yield and water productivity, while for sweet corn applying 75% of full irrigation was the optimal treatment in terms of yield and water productivity.

  10. Testing direct and interactive effects of tree size, stand competition, water balance, heat, and freezing on probability of mortality

    Science.gov (United States)

    Hember, R. A.; Kurz, W. A.; Coops, N. C.

    2016-12-01

    Water stress affects rates of tree mortality in diverse ways. In a previous study, we included standardized water-balance variables as predictors in conventional models of individual-tree mortality drawing on over 8 million observations for 64 North American tree species. We found that probability of tree mortality (Pm) was related to soil-water content (Ws) and/or reference evapotranspiration (ETref) in over 90 percent of the species samples and that sensitivity to water-balance variables was typically mediated by tree height (h) and aridity class (AC) of the site. Here we expand on the model-building exercise to test the additional hypotheses that: (1) sensitivity of Pm of short trees to water-balance variables increases with stand-level biomass of larger trees (BLS) due to competition among trees for access to soil water; (2) sensitivity of Pm to water-balance variables increases with temperature (T) due either to higher respiration or error in the expression of ETref and (3) sensitivity of Pm to water-balance variables increases with the number of days with frost (DWF) due to decreasing hydraulic conductance associated either with occurrence or avoidance of freezing-induced embolism. We describe whether the hypotheses are supported and how the modifications influence predictions of net ecosystem biomass production (NEBP) of North American forests over 1951-2014.

  11. Oil Palm and Rubber Tree Water Use Patterns: Effects of Topography and Flooding.

    Science.gov (United States)

    Hardanto, Afik; Röll, Alexander; Niu, Furong; Meijide, Ana; Hendrayanto; Hölscher, Dirk

    2017-01-01

    Oil palm and rubber plantations extend over large areas and encompass heterogeneous site conditions. In periods of high rainfall, plants in valleys and at riparian sites are more prone to flooding than plants at elevated topographic positions. We asked to what extent topographic position and flooding affect oil palm and rubber tree water use patterns and thereby influence spatial and temporal heterogeneity of transpiration. In an undulating terrain in the lowlands of Jambi, Indonesia, plantations of the two species were studied in plot pairs consisting of upland and adjacent valley plots. All upland plots were non-flooded, whereas the corresponding valley plots included non-flooded, long-term flooded, and short-term flooded conditions. Within each plot pair, sap flux densities in palms or trees were monitored simultaneously with thermal dissipation probes. In plot pairs with non-flooded valleys, sap flux densities of oil palms were only slightly different between the topographic positions, whereas sap flux densities of rubber trees were higher in the valley than at the according upland site. In pairs with long-term flooded valleys, sap flux densities in valleys were lower than at upland plots for both species, but the reduction was far less pronounced in oil palms than in rubber trees (-22 and -45% in maximum sap flux density, respectively). At these long-term flooded valley plots palm and tree water use also responded less sensitively to fluctuations in micrometeorological variables than at upland plots. In short-term flooded valley plots, sap flux densities of oil palm were hardly affected by flooding, but sap flux densities of rubber trees were reduced considerably. Topographic position and flooding thus affected water use patterns in both oil palms and rubber trees, but the changes in rubber trees were much more pronounced: compared to non-flooded upland sites, the different flooding conditions at valley sites amplified the observed heterogeneity of plot mean

  12. DETERMINATION OF WATER AND DRY MATTER IN ORNAMENTAL TREES UNDER THE CLIMATIC CONDITIONS OF IASI

    Directory of Open Access Journals (Sweden)

    Carmen Lamban

    2015-12-01

    Full Text Available This paper presents some results concerning the determination of water and dry matter through the quantitative gravimetric method in ornamental trees (leaves and branches of Juniperus, Thuja, Chamaecyparis, Picea, Pinus, Abies, Pseudotzuga genera, under the climatic conditions of Iasi. The purpose of carrying on this work is to see if moisture of vegetative part remains under normal limits. The success of propagation, planting, transplanting of woody plants is largely dependant on the presence of water.

  13. DEFICIT IRRIGATION TECHNIQUE FOR REDUCING WATER USE OF TOMATO UNDER POLYTUNNEL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Sladjana SAVIC

    2012-01-01

    Full Text Available The aim of paper was to asses the use of regulated deficit irrigation (RDI for production of two tomato cultivars (Cedrico and Abellus in polytunnels in Serbia. RDI plants received 60% of the water that was applied to FI plants and significant saving of water for irrigation and increased in irrigation water use efficiency (IWUE were achieved. Yield data for Cedrico cultivar showed no differences between RDI and FI, while due to the bigger sensitivity to drought, yield of Abellus was reduced under RDI. In general, fruit quality (soluble solids, titrable acidity was sustained or improved in both cultivars under RDI. Economic analyses showed that due to the current low prices of water and electricity in Serbia, the profit increase of Cedrico, similarly to the previously trialed cultivar Amati, was not high under RDI comparing to FI. Reduction of yield and consequent profit for Abellus, indicated that for future commercial growing of tomato under RDI should be used drought resistant cultivars.

  14. Deficit irrigation principles applied to olive orchard in Slovene Istria

    Directory of Open Access Journals (Sweden)

    Maja PODGORNIK

    2015-11-01

    Full Text Available The olive tree has anatomical-morphological and physiological adaptations which enable it to cope well with dry conditions and water deficits. However, if water shortage occurs during the development phases (shoot growth, flower bud development, bloom, fruit set, cell division and enlargement and oil accumulation, which are the most susceptible to stress, it can also have a negative effect on the growth and productivity of olive trees. The Slovenian Istria is facing with increased risk of drought. Due to increased occurrence and intensity of agricultural droughts controlled deficit irrigation will become an inevitable element of agricultural practice in Slovene Istria.

  15. Water-borne hyphomycetes in tree canopies of Kaiga (Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Naga M. Sudheep

    2013-12-01

    Full Text Available The canopy samples such as trapped leaf litter, trapped sediment (during summer, stemflow and throughfall (during monsoon from five common riparian tree species (Artocarpus heterophyllus, Cassia fistula, Ficus recemosa, Syzygium caryophyllatum and Xylia xylocarpa in Kaiga forest stand of the Western Ghats of southwest India were evaluated for the occurrence of water-borne hyphomycetes. Partially decomposed trapped leaf litter was incubated in bubble chambers followed by filtration to assess conidial output. Sediments accumulated in tree holes or junction of branches were shaken with sterile leaf disks in distilled water followed by incubation of leaf disks in bubble chamber and filtration to find out colonized fungi. Stemflow and throughfall samples were filtered directly to collect free conidia. From five canopy niches, a total of 29 water-borne hyphomycetes were recovered. The species richness was higher in stemflow and throughfall than trapped leaf litter and sediments (14-16 vs. 6-10 species. Although sediments of Syzygium caryophyllatum were acidic (5.1, the conidial output was higher than other tree species. Stemflow and throughfall of Xylea xylocarpa even though alkaline (8.5-8.7 showed higher species richness (6-12 species as well as conidial load than rest of the tree species. Flagellospora curvula and Triscelophorus acuminatus were common in trapped leaf litter and sediments respectively, while conidia of Anguillospora crassa and A. longissima were frequent in stemflow and throughfall. Diversity of water-borne hyphomycetes was highest in throughfall of Xylea xylocarpa followed by throughfall of Ficus recemosa. Our study reconfirms the occurrence and survival of diverse water-borne hyphomycetes in different niches of riparian tree canopies of the Western Ghats during wet and dry regimes and predicts their possible role in canopy as saprophytes, endophytes and alternation of life cycle between canopy and aquatic habitats.

  16. Leaf developmental stage modulates metabolite accumulation and photosynthesis contributing to acclimation of Arabidopsis thaliana to water deficit.

    Science.gov (United States)

    Sperdouli, Ilektra; Moustakas, Michael

    2014-07-01

    We examined whether young and mature leaves of Arabidopsis thaliana in their response to mild water deficit (MiWD) and moderate water deficit (MoWD), behave differentially, and whether photosynthetic acclimation to water deficit correlates with increased proline and sugar accumulation. We observed that with increasing water deficit, leaf relative water content decreased, while proline and sugar accumulation increased in both leaf-developmental stages. Under both MiWD and MoWD, young leaves showed less water loss and accumulated higher level of metabolites compared to mature leaves. This, leaf age-related increase in metabolite accumulation that was significantly higher under MoWD, allowed young leaves to cope with oxidative damage by maintaining their base levels of lipid peroxidation. Thus, acclimation of young leaves to MoWD, involves a better homeostasis of reactive oxygen species (ROS), that was achieved among others by (1) increased sugar accumulation and (2) either increased proline synthesis and/or decreased proline catabolism, that decrease the NADPH/NADP(+) ratio, resulting in a higher level of oxidized state of quinone A and thus in a reduced excitation pressure, and by (3) stimulation of the photoprotective mechanism of non-photochemical quenching, that reflects the dissipation of excess excitation energy in the form of harmless heat, thus protecting the plant from the damaging effects of ROS.

  17. Grapevine acclimation to water deficit: the adjustment of stomatal and hydraulic conductance differs from petiole embolism vulnerability.

    Science.gov (United States)

    Hochberg, Uri; Bonel, Andrea Giulia; David-Schwartz, Rakefet; Degu, Asfaw; Fait, Aaron; Cochard, Hervé; Peterlunger, Enrico; Herrera, Jose Carlos

    2017-06-01

    Drought-acclimated vines maintained higher gas exchange compared to irrigated controls under water deficit; this effect is associated with modified leaf turgor but not with improved petiole vulnerability to cavitation. A key feature for the prosperity of plants under changing environments is the plasticity of their hydraulic system. In the present research we studied the hydraulic regulation in grapevines (Vitis vinifera L.) that were first acclimated for 39 days to well-watered (WW), sustained water deficit (SD), or transient-cycles of dehydration-rehydration-water deficit (TD) conditions, and then subjected to varying degrees of drought. Vine development under SD led to the smallest leaves and petioles, but the TD vines had the smallest mean xylem vessel and calculated specific conductivity (k ts). Unexpectedly, both the water deficit acclimation treatments resulted in vines more vulnerable to cavitation in comparison to WW, possibly as a result of developmental differences or cavitation fatigue. When exposed to drought, the SD vines maintained the highest stomatal (g s) and leaf conductance (k leaf) under low stem water potential (Ψs), despite their high xylem vulnerability and in agreement with their lower turgor loss point (ΨTLP). These findings suggest that the down-regulation of k leaf and g s is not associated with embolism, and the ability of drought-acclimated vines to maintain hydraulic conductance and gas exchange under stressed conditions is more likely associated with the leaf turgor and membrane permeability.

  18. Tree water use and rainfall partitioning in a mature poplar-pasture system.

    Science.gov (United States)

    Guevara-Escobar, A.; Edwards, W. R. N.; Morton, R. H.; Kemp, P. D.; Mackay, A. D.

    2000-01-01

    Traditionally, poplars (Populus) have been planted to control erosion on New Zealand's hill-slopes, because of their capacity to dry out and bind together the soil, by reducing effective rainfall and increasing evapotranspiration and soil strength. However, the effect of widely spaced poplars on the partitioning of soil water and rainfall has not been reported. This study determined rainfall partitioning for 18 mid-spring days in a mature P. deltoides (Bart. ex Marsh, Clone I78)-pasture association (37 stems per hectare, unevenly spaced at 16.4 +/- 0.4 m) and compared it with a traditional open pasture system in grazed areas of a hill environment. Tree transpiration was measured by the heat pulse technique. A time-driven mathematical model was used to set a zero offset, adjust anomalous values and describe simultaneous sap velocity time courses of trees. The model showed that daylight sap flow velocities can be represented with a nonlinear Beta function (R(2) > 0.98), and differences in the parameters representing the initiation, duration and conformation of the sap velocity can be tested statistically to discern tree transpiration differences during the day. Evapotranspiration was greater for the poplar-pasture association than for the open pasture (2.7-3.0 versus 2.2 mm day(-1)). The tree canopy alone contributed 0.92 mm day(-1) as transpiration and 1.37 mm day(-1) as interception, whereas evapotranspiration of the pasture understory was only 0.4-0.6 mm day(-1). Despite the higher water use of the poplar-pasture association, soil water in the 0-300 mm soil stratum was higher than, or similar to, that of the open pasture. Tree shading decreased evapotranspiration and pasture accumulation under the trees.

  19. Differential Antioxidative Responses to Water Deficit Among four Barley (Hordeum vulgare L. Genotypes

    Directory of Open Access Journals (Sweden)

    Z Amini

    2013-08-01

    Full Text Available Future climate changes are expected to increase risks of drought, which already represent the most common stress factor for stable barley (Hordeum vulgare L. production in Iran. Up to now, extensive research projects have been done to study effects of drought stress on the antioxidant enzyme activity. While there is a few works of such studies on the field condition. In order to study of water deficit effects on the antioxidant enzymes activities as a secondary stress, we evaluate the effects of mild and severe drought stress on activities of antioxidative enzymes including superoxide dismutases, ascorbate peroxidase, catalase and peroxidase, among four barley genotypes, differing in the capacity to maintain the grain yield under drought condition during beginning on anthesis, kernel watery ripe and late milk stages under field condition. Results showed that drought increased the activity of antioxidant enzymes in all genotypes. At beginning of anthesis, POX activity of Q22 was higher than it in other genotypes ( P

  20. Can deuterium tracing be used for reliably estimating water use of tropical trees and bamboo?

    Science.gov (United States)

    Schwendenmann, Luitgard; Dierick, Diego; Köhler, Michael; Hölscher, Dirk

    2010-07-01

    Reliable estimates of water use by trees and other woody plants are crucial for an improved understanding of plant physiology and for water resource management. Since the 1980s, the thermal dissipation probe (TDP) method has been widely applied in trees, proved to be fairly accurate but is challenging in remote areas. Also in the 1980s, the deuterium (D(2)O or deuterium oxide) tracing method was proposed, which so far has less often been applied. However, deuterium tracing requires less sophisticated equipment in the field and new analytical methods reduce costs and increase sample throughput. The objectives of this study were (i) to compare plant water use estimates of the TDP and D(2)O method and (ii) to determine whether the D(2)O method is appropriate for assessing absolute magnitudes of plant water use. The two methods were employed on five tropical tree species and a bamboo species growing in a reforestation stand in the Philippines and an agroforestry system in Indonesia. For bamboo, an increase in D(2)O values in neighbouring, non-labelled culms suggests that injected D(2)O was partly redistributed among culms, which would seriously limit the accurate estimation of water use for the target culm. For trees, water use estimates resulting from the D(2)O tracing method were proportional to the TDP results (r(2) = 0.85, P < 0.001), but absolute values were, on average, about seven times higher. This overestimation may be due to the assumptions underlying the D(2)O tracing method, such as the conservation of tracer mass, not being met. Further, it cannot be excluded that underestimation of water use by the TDP method contributed partly to the observed difference. However, when considering known sources of error, a large part of the observed difference remains unexplained. Based on our results, the use of the D(2)O tracing method cannot be recommended without further experimental testing if absolute values of whole-plant water use are a major goal. However, the D

  1. Water and forests in the Mediterranean hot climate zone: a review based on a hydraulic interpretation of tree functioning

    Energy Technology Data Exchange (ETDEWEB)

    Soares David, T.; Assunção Pinto, C.; Nadezhdina, N.; Soares David, J.

    2016-07-01

    Aim of the study: Water scarcity is the main limitation to forest growth and tree survival in the Mediterranean hot climate zone. This paper reviews literature on the relations between water and forests in the region, and their implications on forest and water resources management. The analysis is based on a hydraulic interpretation of tree functioning. Area of the study: The review covers research carried out in the Mediterranean hot climate zone, put into perspective of wider/global research on the subject. The scales of analysis range from the tree to catchment levels. Material and Methods: For literature review we used Sc opus, Web of Science and Go ogle Scholar as bibliographic databases. Data from two Quercus suber sites in Portugal were used for illustrative purposes. Main results: We identify knowledge gaps and discuss options to better adapt forest management to climate change under a tree water use/availability perspective. Forest management is also discussed within the wider context of catchment water balance: water is a constraint for biomass production, but also for other human activities such as urban supply, industry and irrigated agriculture. Research highlights: Given the scarce and variable (in space and in time) water availability in the region, further research is needed on: mapping the spatial heterogeneity of water availability to trees; adjustment of tree density to local conditions; silviculture practices that do not damage soil properties or roots; irrigation of forest plantations in some specific areas; tree breeding. Also, a closer cooperation between forest and water managers is needed. (Author)

  2. Infiltration and water balance modeling along a toposequence in a rubber tree plantation of NE Thailand

    Science.gov (United States)

    Hammecker, Claude; Seltacho, Siwaporn; Suvanang, Nopmanee; Do, Frederic; Angulo-Jaramillo, Rafael

    2015-04-01

    Northeast of Thailand, is a plateau at 200 m AMSL with a typical undulating landscape. Traditionally the lowlands were dedicated to paddy fields and the uplands covered by Dipterocarpus forest. However development of cash crops during the last decades has led to intensive land clearing in the uplands and to modifications at a regional scale of the water balance in the critical zone with increasing runoff and soil erosion. Recent international demand increase for natural rubber motivated many local farmers to shift from these cash crops towards rubber-tree (Heva Brasiliensis) plantations. However these land use changes have been undertaken without considering the climatic and edaphic specificity of the region, which are not well adapted to the growth of rubber tree (rainfall lower than recommended and sandy soils with low fertility). Therefore, in order to assess and try to predict the environmental consequences (water resources, water-table, ..) of the development of rubber tree plantations in this area, a small watershed in the region ok Khon Kaen has been selected to follow the infiltration and to monitor the different components of the water balance along a toposequence. A six years monitoring of the main components of water balance along a toposequence associated to numerical simulation were used to quantify and try to forecast the evolution of the water use and water resources. Unsaturated soil properties were determined at different depths, in various positions along the toposequence. Experimental results supported by modeling of 2D water flow with HYDRUS3D show clearly that infiltration is blocked by a clayey layer on top of the bedrock and conditioned the occurrence of a perched watertable during the rainy seasons. Most of the soil water flow was found to be directed laterally during the rainy season. The deep groundwater was found to be fed from the lower part of toposequence in the thalweg. The transpiration rate measured on the trees at this stage of

  3. Quantification of transpirable soil water explains tree water use dynamics in a semi-arid pine forest

    Science.gov (United States)

    Klein, T.; Cohen Hilaleh, E.; Raz Yaseef, N.; Rotenberg, E.; Preisler, Y.; Cohen, S.; Yakir, D.

    2012-04-01

    The relationships between soil water dynamics and tree water use is essential for understanding the controls over forest productivity and sustainability. This, in turn, often relies on measurements of soil water content (SWC), and calculated 'fraction' of water availability (above a fixed minimum). This approach has some limitations because plant water use seems to correspond better with changes in water potential and absolute moisture quantity. Using data from a semi-arid Pinus halepensis forest site, a soil water potential threshold for tree transpiration (Tt, measured as sap flow) of -2.0 MPa is obtained. Using this threshold value and layer-specific water retention curves allows the calculation of the total soil column water content available for tree transpiration, the transpirable water content (tSWC), as well as its distribution with depth. Simultaneous examination of the seasonal changes in tSWC and Tt showed that initially Tt was 0.2-0.4 mm d-1 when tSWC > 0 only above 20 cm. Maximal Tt values reached 1.3 mm d-1 in spring, when tSWC > 0 was calculated only below 20 cm. The results indicated that onset of the productive season rely on shallow tSWC and peak activity on tSWC in deeper layers. Root density profiles showed maximum values (334 fine roots m-2) at the 20-40 cm soil layer, and ^18O measurements of tree sap water confirmed that this layer is the source of Tt in the dry season. Limited water infiltration to depth below 40 cm was associated with high water retention (51% clay, maintaining tSWC near zero at all time). The above analysis using the tSWC terms provided a basis to explain the observations of above 90% recovery of annual precipitation in the ecosystem evapotranspiration, and ~60% in Tt. This approach also allows the estimation of the onset and termination of the productive season associated with gross primary productivity (GPP), which depends on tSWC > 0.

  4. Tree specific traits vs. stand level characteristics - assessing the source depths of plant water uptake in a mixed forest stand

    Science.gov (United States)

    Seeger, Stefan; Brinkmann, Nadine; Kahmen, Ansgar; Weiler, Markus

    2017-04-01

    Due to differences in fine root distributions, physiological root characteristics and plant plasticity, the spatial and temporal characteristics of plant water uptake are expected to vary between different tree species. This has implications on the overall water budget of a forest stand as well as on the drought sensitivity of particular trees. A four-year time series of climate data, soil moisture, and stable water isotopes in soil and tree xylem was used to investigate plant water uptake dynamics of four tree species (beech - Fagus sylvatica, spruce - Picea abies, ash - Fraxinus excelsior and maple - Acer pseudoplatanus) in a mixed forest stand. Modeling with a modified version of the soil hydrological model Hydrus-1D allowed us to simulate continuous time series of stable water isotopes in plant water uptake, which were compared to the measured values in tree xylem water and soil water. We found that different estimated species specific fine root distributions and root water uptake parameters lead to very similar simulated water balances and soil water isotope depth profiles for all four species. According to our simulations, differences in evaporative demand (i.e. LAI) had the biggest influence on water uptake and soil water distributions. Comparing the isotopic signatures of simulated root water uptake and measured xylem water, the simulations for beech were most suited to predict the observed signatures of all four species. This indicates that isolated, tree specific parametrized 1-D simulations are not suited to predict actual water uptake of different trees in a mixed stand. Due to overlapping root spaces dominant trees (in our case beeches with an LAI of around 5.5) may influence the soil water storage below accompanying trees (spruces, ashes and maples with LAIs between 1.8 and 3.1) in a degree that their actual water uptake cannot be predicted with 1-D simulations based on their smaller LAI values. Consequently, for a mixed forest stand the interplay of

  5. Alterations in osmoregulation, antioxidant enzymes and indole alkaloid levels in Catharanthus roseus exposed to water deficit.

    Science.gov (United States)

    Jaleel, C Abdul; Manivannan, P; Kishorekumar, A; Sankar, B; Gopi, R; Somasundaram, R; Panneerselvam, R

    2007-10-01

    Catharanthus roseus (L.) G. Don plants were grown in different water regimes in order to study the drought induced osmotic stress and proline (PRO) metabolism, antioxidative enzyme activities and indole alkaloid accumulation. The plants under pot culture were subjected to 10, 15 and 20 days interval drought (DID) stress from 30 days after sowing (DAS) and regular irrigation was kept as control. The plants were uprooted on 41DAS (10DID), 46DAS (15DID) and 51DAS (20DID). The drought stressed plants showed increased aminoacid (AA), glycine betaine (GB) and PRO contents and decreased proline oxidase (PROX) and increased gamma-glutamyl kinase (gamma-GK) activities when compared to control. The antioxidative enzymes like peroxidase (POX) and polyphenol oxidase (PPO) increased to a significant level in drought stressed plants when compared to control. The drought stressed C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to well-watered control plants. Our results suggest that the cultivation of medicinal plants like C. roseus in water deficit areas would increase its PRO metabolism, osmoregulation, defense system and the level of active principles.

  6. Seasonal variation in canopy reflectance and its application to determine the water status and water use by citrus trees in the Western Cape, South Africa

    CSIR Research Space (South Africa)

    Dzikiti, Sebinasi

    2011-08-01

    Full Text Available This study describes the diurnal and seasonal dynamics of the canopy reflectance, water use and water status of Midknight Valencia citrus trees under semi-arid conditions. Hyperspectral canopy reflectance data was collected on 30 trees at monthly...

  7. Effect of Super Absorbent Polymer and Irrigation Deficit on Water Use Efficiency, Growth and Yield of Cotton

    Directory of Open Access Journals (Sweden)

    Hamid-Reza FALLAHI

    2015-09-01

    Full Text Available Sustainable use of water resources in agriculture is a necessity for many arid countries. In order to investigate the effect of water deficit, irrigation after 120 (control, 155 (moderate water stress and 190 mm (sever water stress pan evaporation and super absorbent polymer rates (SAP (0, 30, 60 and 90 kg ha-1 on growth, yield and water use efficiency of cotton, an experiment was conducted as split plot based on a randomized complete block design with three replications. Moreover, the effect of water quality (distilled water and solutions of 0.25, 0.5, 0.75, 1 and 1.25% NaCl was investigated on water holding capacity by SAP. Results revealed that moderate water stress (irrigation intervals of aprox. 15 days along with 60 kg ha-1 SAP application was the best treatment in terms of growth and yield indices of cotton. The results for plant height, plant dry weight, boll number per plant and fiber yield in this treatment were 16, 28, 42 and 10% higher than control treatment, respectively. Water deficit and SAP application improved the water use efficiency (WUE of cotton. The amount of WUE in moderate water stress treatment along with consumption of 60 or 90 kg ha-1 SAP was 26% higher than for control treatment. In addition, water holding capacity by SAP in distilled water treatment was 7 times higher than in the case of 1.25% NaCl solution. The overall results showed that irrigation deficit and SAP application are two appropriate strategies for crop production in areas affected by drought stress, especially if low saline water sources are used.

  8. Responses of apple fruit size to tree water status and crop load.

    Science.gov (United States)

    Naor, A; Naschitz, S; Peres, M; Gal, Y

    2008-08-01

    The combined effects of irrigation rate and crop load on apple yield and fruit size were examined in two commercial apple orchards (cv. Golden Delicious) in a semi-arid zone. The irrigation rates applied were 1, 3 and 7 mm day(-1), and the two fruit thinning treatments involved adjusting crop load to 100 and 300 fruits per tree at Ortal and 50 and 150 fruits per tree at Matityahu. Unthinned trees served as the control. The fruit from each tree was picked separately, and fruit size distribution was determined with a commercial grading machine. Midday stem water potentials varied from -0.9 to -2.8 MPa, crop load varied from 80,000 to 1,900,000 fruit ha(-1) and crop yield varied from 10 to 144 Mg ha(-1). Midday stem water potential decreased with increasing crop load in all irrigation treatments at Matityahu, but only in the 1 mm day(-1) treatment at Ortal. The extent of the lowering of midday stem water potential by crop load decreased with increasing soil water availability. At both orchards, a similar response of total crop yield to crop load on a per hectare basis was observed. Mean fruit mass and relative yield of fruit > 70 mm in diameter increased with midday stem water potential, with the low crop loads having similar but steeper slopes than the high crop load. The responses of mean fruit mass and relative yield of fruit > 70 mm in diameter to midday stem water potential were similar at both orchards, perhaps indicating that thresholds for irrigation scheduling are transferable to other orchards within a region. Factors that may limit the transferability of these thresholds are discussed.

  9. Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

    Science.gov (United States)

    Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2015-04-01

    Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying

  10. Surface Water Storage Capacity of Twenty Tree Species in Davis, California.

    Science.gov (United States)

    Xiao, Qingfu; McPherson, E Gregory

    2016-01-01

    Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage capacity is known to vary widely among tree species, but it is little studied. This research measured surface storage capacities of 20 urban tree species in a rainfall simulator. The measurement system included a rainfall simulator, digital balance, digital camera, and computer. Eight samples were randomly collected from each tree species. Twelve rainfall intensities (3.5-139.5 mm h) were simulated. Leaf-on and leaf-off simulations were conducted for deciduous species. Stem and foliar surface areas were estimated using an image analysis method. Results indicated that surface storage capacities varied threefold among tree species, 0.59 mm for crape myrtle ( L.) and 1.81 mm for blue spruce ( Engelm.). The mean value across all species was 0.86 mm (0.11 mm SD). To illustrate application of the storage values, interception was simulated and compared across species for a 40-yr period with different rainfall intensities and durations. By quantifying the potential for different tree species to intercept rainfall under a variety of meteorological conditions, this study provides new knowledge that is fundamental to validating the cost-effectiveness of urban forestry as a green infrastructure strategy and designing functional plantings. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  11. Evaluation of Selected Soybean Genotypes (GLYCINE MAX L. by Physiological Responses during Water Deficit

    Directory of Open Access Journals (Sweden)

    Eleonora KRIVOSUDSKA

    2013-06-01

    Full Text Available During the experiments were monitored the following varieties: Impala (South African Republic, Maverick (USA, Rankoshi No.1h (Japan and their reactions to the water supply at the beginning of the growth stage R1 and R2 blooming in an interaction with the Nitrazon inoculation of the seeds before a sowing. Mentioned genetic resources were provided for our research purposes by the Plant Production Research Center PRRC Piesany, Gene Bank of the Slovak Republic. Seeding of the particular soy genotypes was made into the containers whilst 50% of seed corn from each genotype was before the sowing inoculated by the usage of Nitrazon inoculant (supplier: Agrokomp, spol. s.r.o., Modra. Water stress was secured by an irrigation interruption for a 7-day period in the mentioned growth stage. This stress had a negative impact on the relative water content in RWC plants, proline content, osmotic potential, SPAD, stress index as well as an amount of nodules on the roots by the all monitored varieties. According to an evaluation of the mentioned indicators more significant proline accumulation was confirmed by the genotype Maverick especially by the variant exposed to water deficit 3,25 micro mol g 1 FW according to the calculations on 100 percent RWC without the inoculant Nitrazon use and inoculating variant 2.99 micro mol g 1 FW according to calculations on 100 percent RWC. Variety MAVERICK had got the best reaction to water stress and even more noticeable resistance to the stress was monitored in the variant with Nitrazon application in the foregoing seed treatment of soybean seeds. The opposite response to the inoculation was monitored by IMPALA genotype when RWC had dropped to 41.77% in the comparison with the variant without inoculation where RWC had dropped to 61.86%.

  12. Whole-tree water use efficiency is decreased by ambient ozone and not affected by O3-induced stomatal sluggishness.

    Directory of Open Access Journals (Sweden)

    Yasutomo Hoshika

    Full Text Available Steady-state and dynamic gas exchange responses to ozone visible injury were investigated in an ozone-sensitive poplar clone under field conditions. The results were translated into whole tree water loss and carbon assimilation by comparing trees exposed to ambient ozone and trees treated with the ozone-protectant ethylenediurea (EDU. Steady-state stomatal conductance and photosynthesis linearly decreased with increasing ozone visible injury. Dynamic responses simulated by severing of a leaf revealed that stomatal sluggishness increased until a threshold of 5% injury and was then fairly constant. Sluggishness resulted from longer time to respond to the closing signal and slower rate of closing. Changes in photosynthesis were driven by the dynamics of stomata. Whole-tree carbon assimilation and water loss were lower in trees exposed to ambient O(3 than in trees protected by EDU, both under steady-state and dynamic conditions. Although stomatal sluggishness is expected to increase water loss, lower stomatal conductance and premature leaf shedding of injured leaves aggravated O(3 effects on whole tree carbon gain, while compensating for water loss. On average, WUE of trees exposed to ambient ozone was 2-4% lower than that of EDU-protected control trees in September and 6-8% lower in October.

  13. Tomato Yield and Water Use Efficiency - Coupling Effects between Growth Stage Specific Soil Water Deficits

    DEFF Research Database (Denmark)

    Chen, Si; Zhenjiang, Zhou; Andersen, Mathias Neumann

    2015-01-01

    of the regression model showed that the maximum yield, 1166 g per plant, was obtained by the combination of θ1 (c. 28% ASW), θ2 (c. 82% ASW), θ3 (c. 92% ASW), θ4 (c. 92% ASW), and θ5 (c. 92% ASW). This result may guide irrigation scheduling to achieve higher tomato yield and WUE based on specific soil water...... effects of ASW in two growth stages were between θ2 and θ5, θ3. In both cases a moderate θ2 was a precondition for maximum yield response to increasing θ5 and θ3. Sensitivity analysis revealed that yield was most sensitive to soil water content at fruit maturity (θ5). Numerical inspection...

  14. Water relations and organic solutes production in four umbu tree (Spondias tuberosa) genotypes under intermittent drought

    OpenAIRE

    Silva,E.C.; NOGUEIRA, R. J. M. C.; VALE, F. H. A.; MELO, N.F. de; ARAUJO, F. P. de

    2009-01-01

    In order to evaluate changes in leaf water potential (ψw) and solute accumulation induced by intermittent drought, an research was performed under greenhouse conditions using four umbu tree genotypes (GBU 44, GBU 48, GBU 50 and GBU 68) and two water treatments (control and stressed by withholding water), with four replicates. The ψw was measured in four-hour intervals during a 24-hour period at the first stomatal closure and at the end of the experimental period. Carbohydrates, amin...

  15. Tree water storage and its diurnal dynamics related to sap flow and changes in stem volume in old-growth Douglas-fir trees.

    Science.gov (United States)

    Cermák, Jan; Kucera, Jiri; Bauerle, William L; Phillips, Nathan; Hinckley, Thomas M

    2007-02-01

    Diurnal and seasonal tree water storage was studied in three large Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees at the Wind River Canopy Crane Research site. Changes in water storage were based on measurements of sap flow and changes in stem volume and tissue water content at different heights in the stem and branches. We measured sap flow by two variants of the heat balance method (with internal heating in stems and external heating in branches), stem volume with electronic dendrometers, and tissue water content gravimetrically. Water storage was calculated from the differences in diurnal courses of sap flow at different heights and their integration. Old-growth Douglas-fir trees contained large amounts of free water: stem sapwood was the most important storage site, followed by stem phloem, branch sapwood, branch phloem and needles. There were significant time shifts (minutes to hours) between sap flow measured at different positions within the transport system (i.e., stem base to shoot tip), suggesting a highly elastic transport system. On selected fine days between late July and early October, when daily transpiration ranged from 150 to 300 liters, the quantity of stored water used daily ranged from 25 to 55 liters, i.e., about 20% of daily total sap flow. The greatest amount of this stored water came from the lower stem; however, proportionally more water was removed from the upper parts of the tree relative to their water storage capacity. In addition to lags in sap flow from one point in the hydrolic pathway to another, the withdrawal and replacement of stored water was reflected in changes in stem volume. When point-to-point lags in sap flow (minutes to hours near the top and stem base, respectively) were considered, there was a strong linear relationship between stem volume changes and transpiration. Volume changes of the whole tree were small (equivalent to 14% of the total daily use of stored water) indicating that most stored water came from

  16. Leaf and whole-tree water use relations of Australian rainforest species

    Science.gov (United States)

    Ishida, Yoko; Laurance, Susan; Liddell, Michael; Lloyd, Jonathan

    2015-04-01

    Climate change induces drought events and may therefore cause significant impact on tropical rainforests, where most plants are reliant on high water availability - potentially affecting the distribution, composition and abundance of plant species. Using an experimental approach, we are studying the effects of a simulated drought on lowland rainforest plants at the Daintree Rainforest Observatory (DRO), in tropical northern Australia. Before to build up the rainout infrastructure, we installed sap flow meters (HRM) on 62 rainforest trees. Eight tree species were selected with diverse ecological strategies including wood density values ranging from 0.34 to 0.88 g/cm3 and could be replicated within a 1ha plot: Alstonia scholaris (Apocynaceae), Argyrondendron peralatum (Malvaceae), Elaeocarpus angustifolius (Elaeocarpaceae), Endiandra microneura (Lauraceae), Myristica globosa (Myristicaceae), Syzygium graveolens (Myrtaceae), Normanbya normanbyi (Arecaceae), and Castanospermum australe (Fabaceae). Our preliminary results from sap flow data obtained from October 2013 to December of 2014 showed differences in the amount of water used by our trees varied in response to species, size and climate. For example Syzygium graveolens has used a maximum of 60 litres/day while Argyrondendrum peralatum used 13 litres/day. Other potential causes for differential water-use between species and the implications of our research will be discussed. We will continue to monitor sap flow during the rainfall exclusion (2014 to 2016) to determine the effects of plant physiological traits on water use strategies.

  17. Effects of Water Deficit Stress on Several Quantitative and Qualitative Characteristics of Canola (Brassica napus L. Cultivars

    Directory of Open Access Journals (Sweden)

    Mohammad HOSSEINI

    2011-08-01

    Full Text Available Water deficit stress considered as one of the most important limiting factors for oil seed canola (Brassica napus L. growth and productivity in Iran. To evaluate the effects of water deficit stress on some qualitative and quantitative characteristics of canola cultivars, this experiment in a greenhouse trial carried out as factorial based on completely randomized design with three replications in Shahid Chamran University of Ahwaz (Iran. Canola cultivars, including ‘Hyola 308’, ‘Hyola 401’ and ‘RGS 003’ as first factor, and the second one was three levels of water deficit stress, including stress at early stem elongation stage to early flowering (D1, early flowering stage to early emergence of sacs (D2, beginning of stem elongation stage to early emergence of sacs (D3 and normal irrigation (C, as check. Results showed that the interaction between water deficit stress and cultivars affected biological yield, seed oil yields and harvest index (p≤0.01, dry matter and economic yield (p≤0.05. Water deficit stress reduced grain oil yields. ‘Hyola 308’ under stress at beginning stem elongation stage to early flowering had the lowest oil yields (1.1 g plants-1 and ‘Hyola 401’ under non-stress conditions showed highest oil yields (4.3 g plants-1. The decrease of oil yields at the flowering stage to stem elongation stage was more than the other stages. In addition, water deficit stress reduced harvest index in the three stress levels due to reduced economic yield and reduced biological yield. Stress susceptibility index for ‘Hyola 401’ at the beginning of stem elongation stage to early emergence of sacs was 0.914 and the ‘Hyola 308’ showed 1.12 at the beginning of stem elongation stage to early emergence of sacs respectively, which it can implies that ‘Hyola 308’ is more sensitive than ‘Hyola 401’ to water deficit stress.

  18. Water relations and photosynthesis as criteria for adequate irrigation management in 'Tahiti' lime trees

    Directory of Open Access Journals (Sweden)

    Silva Cláudio Ricardo da

    2005-01-01

    Full Text Available Irrigation scheduling based on soil moisture status is one of the most useful methods because of its practicality and low cost. The effects of available soil water depletion on evapotranspiration (ETc, transpiration (E, leaf water potential at predawn (psiP and midday (psiM, stomatal conductance (gs and net CO2 assimilation (A in lime 'Tahiti' trees (Citrus latifolia were evaluated to improve irrigation schedule and minimize water use without causing water stress. The trees were spaced 7 4 m and drip-irrigated by four drippers with the available soil water content (AWC depleted by suspension of irrigation (40 days. Leaf water potential was measured on a pressure chamber (psiP and psiM and leaf gas exchange was measured by infrared gas analyzer (E, gs and A. Evapotranspiration was determined with the aid of weighing lysimeter. Water soil content and potential (psiS were monitored with TDR probes and tensiometers, respectively, installed at 0.3, 0.6 and 0.9 m depths. Meteorological variables were monitored with an automatic weather station in the experimental area. The threshold AWC level for the onset of ETc decline was 43%, and 60% for gs, A, E and Y P. Also, psiP was more sensitive to AWC than psiM, and is therefore a better tool for irrigation. When AWC was around 60%, values of psiP and psis were -0.62 MPa and -48.8 kPa, respectively.

  19. Rooting depth: a key trait connecting water and carbon metabolism of trees

    Science.gov (United States)

    Savi, Tadeja; Dal Borgo, Anna; Casolo, Valentino; Bressan, Alice; Stenni, Barbara; Zini, Luca; Bertoncin, Paolo; Nardini, Andrea

    2015-04-01

    Drought episodes accompanied by heat waves are thought to be the main cause of increasing rates of tree decline and mortality in several biomes with consequent ecological/economical consequences. Three possible and not mutually exclusive mechanisms have been proposed to be the drivers of this phenomenon: hydraulic failure caused by massive xylem cavitation and leading to strong reduction of root-to-leaf water transport, carbon starvation caused by prolonged stomatal closure and leading to impairment of primary and secondary metabolism, and finally attacks of biotic agents. The different mechanisms have been reported to have different relevance in the different species. We analyzed the seasonal changes of water relations, xylem sap isotopic composition, and concentration of non-structural carbohydrates in four different woody species co-occurring in the same habitat during a summer drought. Analysis of rain and deep soil water isotopic composition were also performed. Different species showed differential access to deep water sources which influences the gas exchanges and the concentration of non structural carbohydrates (NSC) during the dry season. Species with access to deeper water maintained higher NSC content and were also able to better preserve the integrity of the water transport pathway. On the basis of our results, we propose that rooting depth is a key trait connecting water and carbon plant metabolism, thus mediating the likelihood of hydraulic failure vs carbon starvation in trees subjected to global warming.

  20. Water deficit enhances the transmission of plant viruses by insect vectors.

    Directory of Open Access Journals (Sweden)

    Manuella van Munster

    Full Text Available Drought is a major threat to crop production worldwide and is accentuated by global warming. Plant responses to this abiotic stress involve physiological changes overlapping, at least partially, the defense pathways elicited both by viruses and their herbivore vectors. Recently, a number of theoretical and empirical studies anticipated the influence of climate changes on vector-borne viruses of plants and animals, mainly addressing the effects on the virus itself or on the vector population dynamics, and inferring possible consequences on virus transmission. Here, we directly assess the effect of a severe water deficit on the efficiency of aphid-transmission of the Cauliflower mosaic virus (CaMV or the Turnip mosaic virus (TuMV. For both viruses, our results demonstrate that the rate of vector-transmission is significantly increased from water-deprived source plants: CaMV transmission reproducibly increased by 34% and that of TuMV by 100%. In both cases, the enhanced transmission rate could not be explained by a higher virus accumulation, suggesting a more complex drought-induced process that remains to be elucidated. The evidence that infected plants subjected to drought are much better virus sources for insect vectors may have extensive consequences for viral epidemiology, and should be investigated in a wide range of plant-virus-vector systems.

  1. Assessing HYDRUS-2D model to estimate soil water contents and olive tree transpiration fluxes under different water distribution systems

    Science.gov (United States)

    Autovino, Dario; Negm, Amro; Rallo, Giovanni; Provenzano, Giuseppe

    2016-04-01

    In Mediterranean countries characterized by limited water resources for agricultural and societal sectors, irrigation management plays a major role to improve water use efficiency at farm scale, mainly where irrigation systems are correctly designed to guarantee a suitable application efficiency and the uniform water distribution throughout the field. In the last two decades, physically-based agro-hydrological models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere (SPA) system. Mechanistic models like HYDRUS 2D/3D (Šimunek et al., 2011) have been proposed to simulate all the components of water balance, including actual crop transpiration fluxes estimated according to a soil potential-dependent sink term. Even though the suitability of these models to simulate the temporal dynamics of soil and crop water status has been reported in the literature for different horticultural crops, a few researches have been considering arboreal crops where the higher gradients of root water uptake are the combination between the localized irrigation supply and the three dimensional root system distribution. The main objective of the paper was to assess the performance of HYDRUS-2D model to evaluate soil water contents and transpiration fluxes of an olive orchard irrigated with two different water distribution systems. Experiments were carried out in Castelvetrano (Sicily) during irrigation seasons 2011 and 2012, in a commercial farm specialized in the production of table olives (Olea europaea L., var. Nocellara del Belice), representing the typical variety of the surrounding area. During the first season, irrigation water was provided by a single lateral placed along the plant row with four emitters per plant (ordinary irrigation), whereas during the second season a grid of emitters laid on the soil was installed in order to irrigate the whole soil surface around the selected trees. The model performance was assessed based on the

  2. Effect of Deficit Irrigation Treatments on Vegetative Characteristics and Quantity and Quality of Golden Delicious Apple

    Directory of Open Access Journals (Sweden)

    I. Arji

    2016-07-01

    Full Text Available Introduction: Since Iran is located in arid and semi-arid region of the world, so consumption and saving of water must be taking into account. Water is often a valuable natural resource, thus proper application methods - for increase water efficiency can be very important. Regulated deficit irrigation (RDI is one of the most important methods to increase water use efficiency and fruit quality. Apple is one of the most important fruit trees from economical point of view. Studies showed that regulated deficit irrigation led to growth reduction in apple trees and sometimes fruit quality increased. The aim of this study was to evaluate the effect deficit irrigation on vegetative growth and fruit quantity and quality of Golden delicious apple trees in Gahvareh region of Kermanshah province. Materials and Methods: This experiment was conducted on 10 years old Golden delicious apple trees in a randomized complete block design with 5 irrigation treatments and three replications during 2006. Three apple trees assigned to each experimental unit. Irrigation treatments were: T1= early deficit irrigation (40% water requirement, T2= early deficit irrigation (60% water requirement, T3= late deficit irrigation (40% water requirement, T4=late deficit irrigation (60% water requirement, T5=control (C (100% water requirement. Early deficit irrigation starts 55 days after full bloom (15th Jun and continued 60 days (16th Aug, while late deficit irrigation starts 115 days after from full bloom (16th Aug and continued 40 days near to harvesting time (23th Sept. Control trees were full irrigated based on water requirement, which calculated based on national water document of Iran and irrigation amount was calculated based on the following formulas: Q=0.0184.L.H3/2 Where Q is volumetric flow rate (liter/Second, L is parshall flume crown length (cm and H is water height (cm. Irrigation time was calculated based on national water document of Iran and volumetric flow rate

  3. Linking xylem water storage with anatomical parameters in five temperate tree species.

    Science.gov (United States)

    Jupa, Radek; Plavcová, Lenka; Gloser, Vít; Jansen, Steven

    2016-06-01

    The release of water from storage compartments to the transpiration stream is an important functional mechanism that provides the buffering of sudden fluctuations in water potential. The ability of tissues to release water per change in water potential, referred to as hydraulic capacitance, is assumed to be associated with the anatomy of storage tissues. However, information about how specific anatomical parameters determine capacitance is limited. In this study, we measured sapwood capacitance (C) in terminal branches and roots of five temperate tree species (Fagus sylvatica L., Picea abies L., Quercus robur L., Robinia pseudoacacia L., Tilia cordata Mill.). Capacitance was calculated separately for water released mainly from capillary (CI; open vessels, tracheids, fibres, intercellular spaces and cracks) and elastic storage compartments (CII; living parenchyma cells), corresponding to two distinct phases of the moisture release curve. We found that C was generally higher in roots than branches, with CI being 3-11 times higher than CII Sapwood density and the ratio of dead to living xylem cells were most closely correlated with C In addition, the magnitude of CI was strongly correlated with fibre/tracheid lumen area, whereas CII was highly dependent on the thickness of axial parenchyma cell walls. Our results indicate that water released from capillary compartments predominates over water released from elastic storage in both branches and roots, suggesting the limited importance of parenchyma cells for water storage in juvenile xylem of temperate tree species. Contrary to intact organs, water released from open conduits in our small wood samples significantly increased CI at relatively high water potentials. Linking anatomical parameters with the hydraulic capacitance of a tissue contributes to a better understanding of water release mechanisms and their implications for plant hydraulics. © The Author 2016. Published by Oxford University Press. All rights

  4. Influence of tree water potential in inducing flowering in Rhododendron arboreum in the central Himalayan region

    OpenAIRE

    Tewari A; Bhatt J; Mittal A

    2016-01-01

    Rise in temperature has been reported as the principal cause of variation in flowering phenology in several tree species around the globe. In this study, we hypothesized that not only temperature but also rainfall periodicity, soil moisture and the related changes of twig water potential (ψ) in winter and early spring are important drivers of bud expansion and flowering in Rhododendron arboreum in central Himalayas. To this purpose, phenological and physiological variables (flowering time, fl...

  5. Ground water chlorinated ethenes in tree trunks: case studies, influence of recharge, and potential degradation mechanism

    Science.gov (United States)

    Don A. Vroblesky; Barton D. Clinton; James M. Vose; Clifton C. Casey; Gregory J. Harvey; Paul M. Bradley

    2004-01-01

    Trichloroethene (TCE) was detected in cores of trees growing above TCE-contaminated ground at three sites: the Carswell Golf Course in Texas, Air Force Plant PJKS in Colorado, and Naval Weapons Station Charleston in South Carolina. This was true even when the depth to water was 7.9 m or when the contaminated aquifer was confined beneath ~3 m of clay. Additional ground...

  6. Seasonal carbon storage and growth in Mediterranean tree seedlings under different water conditions.

    Science.gov (United States)

    Sanz-Pérez, Virginia; Castro-Díez, Pilar; Joffre, Richard

    2009-09-01

    In all Mediterranean-type ecosystems, evergreen and deciduous trees differing in wood anatomy, growth pattern and leaf habit coexist, suggesting distinct adaptative responses to environmental constraints. This study examined the effects of summer water stress on carbon (C) storage and growth in seedlings of three coexisting Mediterranean trees that differed in phenology and wood anatomy characteristics: Quercus ilex subsp. ballota (Desf.) Samp., Quercus faginea Lam. and Pinus halepensis L. Seedlings were subjected to two levels of watering during two consecutive summers and achieved a minimum of -0.5 and -2.5 MPa of predawn water potential in the control and water stress treatment, respectively. Both Quercus species concentrated their growth in the early growing season, demanding higher C in early spring but replenishing C-stores in autumn. These species allocated more biomass to roots, having larger belowground starch and lipid reserves. Quercus species differed in seasonal storage dynamics from P. halepensis. This species allocated most of its C to aboveground growth, which occurred gradually during the growing season, leading to fewer C-reserves. Soluble sugar and starch concentrations sharply declined in August in P. halepensis, probably because reserves support respiration demands as this species closed stomata earlier under water stress. Drought reduced growth of the three species, mainly in Q. faginea and P. halepensis, but not C-reserves, suggesting that growth under water stress conditions is not limited by C-availability.

  7. Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps

    Directory of Open Access Journals (Sweden)

    R. Balestrini

    2013-03-01

    Full Text Available The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors – including nitrogen species and dissolved organic carbon (DOC – and catchment characteristics were evaluated for a range of sites located above the tree line (1950–2650 m a.s.l. at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation and talus (positive relation, explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.

  8. Influence of arbuscular mycorrhiza on growth and reproductive response of plants under water deficit: a meta-analysis.

    Science.gov (United States)

    Jayne, Benjamin; Quigley, Martin

    2014-02-01

    Despite a large body of literature that describes the effects of arbuscular mycorrhizal colonization on plant response to water deficit, reviews of these works have been mainly in narrative form, and it is therefore difficult to quantify the magnitude of the effect. We performed a meta-analysis to examine the effect of mycorrhizal colonization on growth and yield of plants exposed to water deficit stress. Data were compared in the context of annual vs. perennial plants, herbaceous vs. woody plants, field vs. greenhouse conditions, degree of stress, functional group, regions of plant growth, and mycorrhizal and host species. We found that, in terms of biomass measurements, mycorrhizal plants have better growth and reproductive response under water stress compared to non-mycorrhizal plants. When variables such as habit, life cycle, or water stress level are considered, differences in mycorrhizal effect on plant growth between variables are observed. While growth of both annual and perennial plants is improved by symbiosis, perennials respond more favorably to colonization than annuals. Overall, our meta-analysis reveals a quantifiable corroboration of the commonly held view that, under water-deficit conditions, plants colonized by mycorrhizal fungi have better growth and reproductive response than those that are not.

  9. Effect of phosphate solubilizing microorganisms on quantitative and qualitative characteristics of maize (Zea mays L.) under water deficit stress.

    Science.gov (United States)

    Ehteshami, S M R; Aghaalikhani, M; Khavazi, K; Chaichi, M R

    2007-10-15

    The effect of seed inoculation by phosphate solubilizing microorganisms on growth, yield and nutrient uptake of maize (Zea mays L. SC. 704) was studied in a field experiment. Positive effect on plant growth, nutrient uptake, grain yield and yield components in maize plants was recorded in the treatment receiving mixed inoculum of Glomus intraradices (AM) and Pseudomonas fluorescens (Pf). Co-inoculation treatment significantly increased grain yield, yield components, harvest index, grain N and P, soil available P, root colonization percentage and crop WUE under water deficit stress. In some of investigated characteristics under well-watered conditions, chemical fertilizer treatment was higher than double inoculated treatments, but this difference was not significant. Seed inoculation only with AM positively affected the measured parameters as amount as co-inoculated treatments. According to the results showed in contrast to the inoculated treatments with AM+Pf and AM, the application of alone Pf caused a comparatively poor response. Therefore, this microorganism needs to a complement for its activity in soil. All of measured parameters in inoculated treatments were higher than uninoculated treatments under water deficit stress conditions. Furthermore, the investigated characteristics of co-inoculated plants under severe water deficit stress conditions were significantly lower than co-inoculated plants under well-watered and moderate-stressed conditions. Therefore it could be stated, these microorganisms need more time to fix and establishing themselves in soil. The present finding showed that phosphate-solubilizing microorganisms can interact positively in promoting plant growth as well as P uptake of maize plants, leading to plant tolerance improving under water deficit stress conditions.

  10. Water use of a multigenotype poplar short-rotation coppice from tree to stand scale.

    Science.gov (United States)

    Bloemen, Jasper; Fichot, Régis; Horemans, Joanna A; Broeckx, Laura S; Verlinden, Melanie S; Zenone, Terenzio; Ceulemans, Reinhart

    2017-02-01

    Short-rotation coppice (SRC) has great potential for supplying biomass-based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar (Populus) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand-level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow (Fs) measurements on individual plants vs. stand scale eddy covariance flux data during a 39-day intensive field campaign in late summer 2011. Daily stem diameter variation (∆D) was monitored simultaneously with Fs to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆D (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

  11. Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize ( Zea mays l.) in subtropical northeastern Himalayas

    Science.gov (United States)

    Marwein, M. A.; Choudhury, B. U.; Chakraborty, D.; Kumar, M.; Das, A.; Rajkhowa, D. J.

    2017-05-01

    Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ETc) of maize crop under controlled condition (pot experiment) of water deficit (W25-25 % and W50-50 % of field capacity soil moistures) and well watered (W100 = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ETc losses and water use efficiency was also studied. The measured seasonal ETc loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant ( p < 0.05) reduction (by 33-50 %) of seasonal ETc losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha-1 significantly ( p < 0.05) increased ETc losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W25) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W100) while seasonal ETc loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ETc losses while weekly crop ETc loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ETc losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg-1 water and 4.21 to 8.56 g dry matter kg-1, respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ETc loss, growth duration, grain formation, and water use efficiency of maize.

  12. ABA control of plant macroelement membrane transport systems in response to water deficit and high salinity.

    Science.gov (United States)

    Osakabe, Yuriko; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo; Tran, Lam-Son Phan

    2014-04-01

    Plant growth and productivity are adversely affected by various abiotic stressors and plants develop a wide range of adaptive mechanisms to cope with these adverse conditions, including adjustment of growth and development brought about by changes in stomatal activity. Membrane ion transport systems are involved in the maintenance of cellular homeostasis during exposure to stress and ion transport activity is regulated by phosphorylation/dephosphorylation networks that respond to stress conditions. The phytohormone abscisic acid (ABA), which is produced rapidly in response to drought and salinity stress, plays a critical role in the regulation of stress responses and induces a series of signaling cascades. ABA signaling involves an ABA receptor complex, consisting of an ABA receptor family, phosphatases and kinases: these proteins play a central role in regulating a variety of diverse responses to drought stress, including the activities of membrane-localized factors, such as ion transporters. In this review, recent research on signal transduction networks that regulate the function ofmembrane transport systems in response to stress, especially water deficit and high salinity, is summarized and discussed. The signal transduction networks covered in this review have central roles in mitigating the effect of stress by maintaining plant homeostasis through the control of membrane transport systems. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  13. Assessing water stress of desert Tamarugo trees using in situ data and very high spatial resolution remote sensing

    National Research Council Canada - National Science Library

    Chávez Oyanadel, R.O; Clevers, J.G.P.W; Herold, M; Acevedo, E; Ortiz, M

    2013-01-01

    .... One such species is the tree Prosopis tamarugo Phil. Because Tamarugo completely depends on groundwater, it is being threatened by the high water demand from the Chilean mining industry and the human consumption...

  14. Gridded Snow Water Equivalent Reconstruction for Utah Using Forest Inventory and Analysis Tree-Ring Data

    Directory of Open Access Journals (Sweden)

    Daniel Barandiaran

    2017-06-01

    Full Text Available Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE for the period of 1850–1989 using increment cores collected by the U.S. Forest Service, Interior West Forest Inventory and Analysis program (FIA. In the state of Utah, SWE was reconstructed for 38 snow course locations using a combination of standardized tree-ring indices derived from both FIA increment cores and publicly available tree-ring chronologies. These individual reconstructions were then interpolated to a 4-km grid using an objective analysis with elevation correction to create an SWE product. The results showed a significant correlation with observed SWE as well as good correspondence to regional tree-ring-based drought reconstructions. Diagnostic analysis showed statewide coherent climate variability on inter-annual and inter-decadal time-scales, with added geographical details that would not be possible using courser pre-instrumental proxy datasets. This SWE reconstruction provides water resource managers and forecasters with better spatial resolution to examine past variability in snowpack, which will be important as future hydroclimatic variability is amplified by climate change.

  15. Association of water-borne conidial fungi with epiphytic tree fern (Drynaria quercifolia

    Directory of Open Access Journals (Sweden)

    Kishore S. Karamchand

    2013-12-01

    Full Text Available The live and dead tissues, and trapped leaf litter by the epiphytic tree fern Drynaria quercifolia associated with riparian tree species of Konaje (west coast and Sampaje (Western Ghat streams of India during dry (summer and wet (monsoon seasons yielded 37 species of water-borne conidial fungi on bubble chamber incubation. Dead bracket leaves of fern possess the highest species as well as conidia in Konaje, while the trapped leaf litter in Sampaje. During summer, the diversity was highest in bracket leaves in both locations, while in monsoon season it was highest in rhizomes of Konaje and in trapped leaf litter in Sampaje. Even though the conidial output from tissues of Drynaria and trapped leaf litter were not equivalent to stream submerged leaf litter, the species richness ranged between 40% and 75% in Konaje and Sampaje streams. As stable epiphyte, Drynaria exposed to wet and dry regimes in tree canopies of west coast and Western Ghats likely to serve as host for perfect states of water-borne hyphomycetes.

  16. Fault tree analysis for integrated and probabilistic risk analysis of drinking water systems.

    Science.gov (United States)

    Lindhe, Andreas; Rosén, Lars; Norberg, Tommy; Bergstedt, Olof

    2009-04-01

    Drinking water systems are vulnerable and subject to a wide range of risks. To avoid sub-optimisation of risk-reduction options, risk analyses need to include the entire drinking water system, from source to tap. Such an integrated approach demands tools that are able to model interactions between different events. Fault tree analysis is a risk estimation tool with the ability to model interactions between events. Using fault tree analysis on an integrated level, a probabilistic risk analysis of a large drinking water system in Sweden was carried out. The primary aims of the study were: (1) to develop a method for integrated and probabilistic risk analysis of entire drinking water systems; and (2) to evaluate the applicability of Customer Minutes Lost (CML) as a measure of risk. The analysis included situations where no water is delivered to the consumer (quantity failure) and situations where water is delivered but does not comply with water quality standards (quality failure). Hard data as well as expert judgements were used to estimate probabilities of events and uncertainties in the estimates. The calculations were performed using Monte Carlo simulations. CML is shown to be a useful measure of risks associated with drinking water systems. The method presented provides information on risk levels, probabilities of failure, failure rates and downtimes of the system. This information is available for the entire system as well as its different sub-systems. Furthermore, the method enables comparison of the results with performance targets and acceptable levels of risk. The method thus facilitates integrated risk analysis and consequently helps decision-makers to minimise sub-optimisation of risk-reduction options.

  17. Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L. oil plants for biodiesel

    Science.gov (United States)

    Gouveia-Neto, Artur S.; Silva, Elias A., Jr.; Oliveira, Ronaldo A.; Cunha, Patrícia C.; Costa, Ernande B.; Câmara, Terezinha J. R.; Willadino, Lilia G.

    2011-02-01

    Light-emitting-diode induced chlorophyll fluorescence analysis is employed to investigate the effect of water and salt stress upon the growth process of physicnut(jatropha curcas) grain oil plants for biofuel. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit) for a period of time of 30 days. The chlorophyll fluorescence(ChlF) ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the level of stress experienced by the jatropha plants. The ChlF technique data indicated that salinity plays a minor role in the chlorophyll concentration of leaves tissues for NaCl concentrations in the 25 to 200 mM range, and results agreed quite well with those obtained using conventional destructive spectrophotometric methods. Nevertheless, for higher NaCl concentrations a noticeable decrease in the Chl content was observed. The Chl fluorescence ratio analysis also permitted detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed sample in the first 10 days of the experiment when one compared control and nonwatered samples. The results suggest that the technique may potentially be applied as an early-warning indicator of stress caused by water deficit.

  18. Effect of pH on lead removal from water using tree fern as the sorbent.

    Science.gov (United States)

    Ho, Yuh-Shan

    2005-07-01

    The sorption of lead from water onto an agricultural by-product, tree fern, was examined as a function of pH. The sorption processes were carried out using an agitated and baffled system. Pseudo-second-order kinetic analyses were performed to determine the rate constant of sorption, the equilibrium sorption capacity, and the initial sorption rate. Application of the pseudo-second-order kinetics model produced very high coefficients of determination. Results showed the efficiency of tree fern as a sorbent for lead. The optimum pH for lead removal was between 4 and 7, with pH 4.9 resulting in better lead removal. Ion exchange occurred in the initial reaction period. In addition, a relation between the change in the solution hydrogen ion concentration and equilibrium capacity was developed and is presented.

  19. Uniconazole-induced tolerance of soybean to water deficit stress in relation to changes in photosynthesis, hormones and antioxidant system.

    Science.gov (United States)

    Zhang, Mingcai; Duan, Liusheng; Tian, Xiaoli; He, Zhongpei; Li, Jianmin; Wang, Baomin; Li, Zhaohu

    2007-06-01

    This study investigated whether uniconazole confers drought tolerance to soybean and if such tolerance is correlated with changes in photosynthesis, hormones and antioxidant system of leaves. Soybean plants were foliar treated with uniconazole at 50 mg L-1 at the beginning of bloom and then exposed to water deficit stress at pod initiation for 7 d. Uniconazole promoted biomass accumulation and seed yield under both water conditions. Plants treated with uniconazole showed higher leaf water potential only in water-stressed condition. Water stress decreased the chlorophyll content and photosynthetic rate, but those of uniconazole-treated plants were higher than the stressed control. Uniconazole increased the maximum quantum yield of photosystemand ribulose-1,5-bisphosphate carboxylase/oxygenase activity of water-stressed plants. Water stress decreased partitioning of assimilated 14C from labeled leaf to the other parts of the plant. In contrast, uniconazole enhanced translocation of assimilated 14C from labeled leaves to the other parts, except stems, regardless of water treatment. Uniconazole-treated plants contained less GA3, GA4 and ABA under well-watered condition than untreated plants, while the IAA and zeatin levels were increased substantially under both water conditions, and ABA concentration was also increased under water stressed condition. Under water-stressed conditions, uniconazole increased the content of proline and soluble sugars, and the activities of superoxide dismutase and peroxidase in soybean leaves but not the malondialdehyde content or electrical conductivity. These results suggest that uniconazole-induced tolerance to water deficit stress in soybean was related to the changes of photosynthesis, hormones and antioxidant system of leaves.

  20. Photosynthetic traits of five neotropical rainforest tree species: interactions between light response curves and leaf-to-air vapour pressure deficit

    Directory of Open Access Journals (Sweden)

    Marcelo Schramm Mielke

    2005-09-01

    Full Text Available Measurements of leaf gas exchange at different photosynthetic photon flux density (PPFD levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (D on the saturated photosynthetic rate (Amax. All empirical mathematical models seemed to provide a good estimation of the light response parameters. Comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. When the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of D on leaf gas exchange, was a very good method to enhance the performance of the models.Medições das trocas gasosas foliares em diferentes níveis do densidade de fluxo de fótons fotossintéticamente ativos (PPFD foram realizadas com o objetivo de comparar as características fotossintéticas de cinco espécies arbóreas de florestas úmidas neotropicais, com especial ênfase em modelos matemáticos empíricos para estimativa de parâmetros derivados das curvas de resposta à radiação luminosa e dos efeitos da diferença de pressão de vapor entre a folha e o ar (D na taxa fotossintética em saturação luminosa (Amax. Os modelos analisados proporcionaram boas estimativas para os parâmetros derivados das curvas de resposta à radiação luminosa. Comparações entre as características fotossintéticas de diferentes espécies devem sempre considerar os modelos utilizados, seguidas de indicações pormenorizadas das condições microambientais no momento em que os dados foram coletados. Quando a diferença de pressão de vapor não for controlada artificialmente durante as medições, a

  1. Hydrological properties of bark of selected forest tree species. Part 2: Interspecific variability of bark water storage capacity

    Directory of Open Access Journals (Sweden)

    Ilek Anna

    2017-06-01

    Full Text Available The subject of the present research is the water storage capacity of bark of seven forest tree species: Pinus sylvestris L., Larix decidua Mill., Abies alba Mill., Pinus sylvestris L., Quercus robur L., Betula pendula Ehrh. and Fagus sylvatica L. The aim of the research is to demonstrate differences in the formation of bark water storage capacity between species and to identify factors influencing the hydrological properties of bark. The maximum water storage capacity of bark was determined under laboratory conditions by performing a series of experiments simulating rainfall and by immersing bark samples in containers filled with water. After each single experiment, the bark samples were subjected to gravity filtration in a desiccator partially filled with water. The experiments lasted from 1084 to 1389 hours, depending on the bark sample. In all the studied species, bark sampled from the thinnest trees is characterized by the highest water storage capacity expressed in mm H2O · cm-3, while bark sampled from the thickest trees - by the lowest capacity. On the other hand, bark sampled from the thickest trees is characterized by the highest water storage capacity expressed in H2O · cm-2 whereas bark from the thinnest trees - by the lowest capacity. In most species tested, as the tree thickness and thus the bark thickness and the coefficient of development of the interception surface of bark increase, the sorption properties of the bark decrease with bark depth, and the main role in water retention is played by the outer bark surface. The bark of European beech is an exception because of the smallest degree of surface development and because the dominant process is the absorption of water. When examining the hydrological properties of bark and calculating its parameters, one needs to take into account the actual surface of the bark of trees. Disregarding the actual bark surface may lead to significant errors in the interpretation of research

  2. WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO)

    OpenAIRE

    Mohamed FARISSI; Cherki GHOULAM; Abdelaziz BOUIZGAREN

    2014-01-01

    The present study focused the effect of water deficit on agronomic potential and some traits related to forage quality in plants of Moroccan Alfalfa (Medicago sativa L.) populations (Taf 1, Taf 2, Dem and Tata) originated from Oasis and High Atlas of Morocco and an introduced variety from Australia (Siriver). The experiment was conducted under field conditions in experimental station of INRA-Marrakech and under two irrigation treatments. The first treatment was normal irrigation, providing an...

  3. Transcriptomic changes due to water deficit define a general soybean response and accession-specific pathways for drought avoidance.

    Science.gov (United States)

    Shin, Jin Hee; Vaughn, Justin N; Abdel-Haleem, Hussein; Chavarro, Carolina; Abernathy, Brian; Kim, Kyung Do; Jackson, Scott A; Li, Zenglu

    2015-02-03

    Among abiotic stresses, drought is the most common reducer of crop yields. The slow-wilting soybean genotype PI 416937 is somewhat robust to water deficit and has been used previously to map the trait in a bi-parental population. Since drought stress response is a complex biological process, whole genome transcriptome analysis was performed to obtain a deeper understanding of the drought response in soybean. Contrasting data from PI 416937 and the cultivar 'Benning', we developed a classification system to identify genes that were either responding to water-deficit in both genotypes or that had a genotype x environment (GxE) response. In spite of very different wilting phenotypes, 90% of classifiable genes had either constant expression in both genotypes (33%) or very similar response profiles (E genes, 57%). By further classifying E genes based on expression profiles, we were able to discern the functional specificity of transcriptional responses at particular stages of water-deficit, noting both the well-known reduction in photosynthesis genes as well as the less understood up-regulation of the protein transport pathway. Two percent of classifiable genes had a well-defined GxE response, many of which are located within slow-wilting QTLs. We consider these strong candidates for possible causal genes underlying PI 416937's unique drought avoidance strategy. There is a general and functionally significant transcriptional response to water deficit that involves not only known pathways, such as down-regulation of photosynthesis, but also up-regulation of protein transport and chromatin remodeling. Genes that show a genotypic difference are more likely to show an environmental response than genes that are constant between genotypes. In this study, at least five genes that clearly exhibited a genotype x environment response fell within known QTL and are very good candidates for further research into slow-wilting.

  4. Planting Patterns and Deficit Irrigation Strategies to Improve Wheat Production and Water Use Efficiency under Simulated Rainfall Conditions.

    Science.gov (United States)

    Ali, Shahzad; Xu, Yueyue; Ma, Xiangcheng; Ahmad, Irshad; Kamran, Muhammad; Dong, Zhaoyun; Cai, Tie; Jia, Qianmin; Ren, Xiaolong; Zhang, Peng; Jia, Zhikuan

    2017-01-01

    The ridge furrow (RF) rainwater harvesting system is an efficient way to enhance rainwater accessibility for crops and increase winter wheat productivity in semi-arid regions. However, the RF system has not been promoted widely in the semi-arid regions, which primarily exist in remote hilly areas. To exploit its efficiency on a large-scale, the RF system needs to be tested at different amounts of simulated precipitation combined with deficit irrigation. Therefore, in during the 2015-16 and 2016-17 winter wheat growing seasons, we examined the effects of two planting patterns: (1) the RF system and (2) traditional flat planting (TF) with three deficit irrigation levels (150, 75, 0 mm) under three simulated rainfall intensity (1: 275, 2: 200, 3: 125 mm), and determined soil water storage profile, evapotranspiration rate, grain filling rate, biomass, grain yield, and net economic return. Over the two study years, the RF treatment with 200 mm simulated rainfall and 150 mm deficit irrigation (RF2150) significantly (P profit of winter wheat responded positively to simulated rainfall and deficit irrigation under both planting patterns. The 200 mm simulated rainfall amount was more economical than other precipitation amounts, and led to slight increases in soil water storage, total dry matter per plant, and grain yield; there were no significant differences when the simulated rainfall was increased beyond 200 mm. The highest (12,593 Yuan ha(-1)) net income profit was attained using the RF system at 200 mm rainfall and 150 mm deficit irrigation, which also led to significantly higher grain yield, WUE, and RIWP than all other treatments. Thus, we recommend the RF2150 treatment for higher productivity, income profit, and improve WUE in the dry-land farming system of China.

  5. Evaluating effect of biofertilizer on nodulation and soybean (Glycine max L plants growth characteristics under water deficit stress of seed

    Directory of Open Access Journals (Sweden)

    M. Tajik Khaveh

    2016-05-01

    Full Text Available In order to evaluate the effects of biofertilizer on soybean (Glycine max L. seed vigor that produced under water deficit condition and related traits, an experiment was conducted in a factorial layout based of complete randomized block design with four replications at the research greenhouse of Aboureihan campus- Tehran University, Iran. Experimental treatments were include biofertilizer (seed inoculation with Bradyrhizobium japonicum, co-inoculation with Bradyrhizobium japonicum and Pseudomonas fluorescens, co-inoculation with Bradyrhizobium japonicum and Glomus mosseae, Cultivar (Zalta Zalha and Clark×Hobbit line and water deficit stress [irrigation plants after 50 (normal irrigation, 100 (medium stress, 150 (sever stress mm evaporation from pan class A, in parents field]. Results showed that the water deficit stress had negative effects on seed quality and seedling emergence percentage, mean daily seedling emergence, root, leaf and shoot dry weight, number of nodule were decreased. ZaltaZalha cultivar had higher shoot dry weight and number of leaf compared with other cultivars. Applications of biofertilzer was effective on stem diameter, root, leaf and shoot dry weight, number of leaf and nodule and those attributes increased by co-inoculation of Bradyrhizobium japonicum and Glomus mosseae. Also, use of biofertilizer in stress levels was effective on stem dry weight. Stem dry weight was increased by Co-inoculation of cultivar seeds with Bradyrhizobium japonicum and Glomus mosseae.

  6. Precipitation v. River Discharge Controls on Water Availability to Riparian Trees in the Rhône River Delta

    Science.gov (United States)

    Singer, M. B.; Sargeant, C. I.; Vallet-Coulomb, C.; Evans, C.; Bates, C. R.

    2014-12-01

    Water availability to riparian trees in lowlands is controlled through precipitation and its infiltration into floodplain soils, and through river discharge additions to the hyporheic water table. The relative contributions of both water sources to the root zone within river floodplains vary through time, depending on climatic fluctuations. There is currently limited understanding of how climatic fluctuations are expressed at local scales, especially in 'critical zone' hydrology, which is fundamental to the health and sustainability of riparian forest ecosystems. This knowledge is particularly important in water-stressed Mediterranean climate systems, considering climatic trends and projections toward hotter and drier growing seasons, which have the potential to dramatically reduce water availability to riparian forests. Our aim is to identify and quantify the relative contributions of hyporheic (discharge) water v. infiltrated precipitation to water uptake by riparian Mediterranean trees for several distinct hydrologic years, selected to isolate contrasts in water availability from these sources. Our approach includes isotopic analyses of water and tree-ring cellulose, mechanistic modeling of water uptake and wood production, and physically based modeling of subsurface hydrology. We utilize an extensive database of oxygen isotope (δ18O) measurements in surface water and precipitation alongside recent measurements of δ18O in groundwater and soil water and in tree-ring cellulose. We use a mechanistic model to back-calculate source water δ18O based on δ18O in cellulose and climate data. Finally, we test our results via 1-D hydrologic modeling of precipitation infiltration and water table rise and fall. These steps enable us to interpret hydrologic cycle variability within the 'critical zone' and their potential impact on riparian trees.

  7. A biomechanical perspective on the role of large stem volume and high water content in baobab trees (Adansonia spp.; Bombacaceae).

    Science.gov (United States)

    Chapotin, Saharah Moon; Razanameharizaka, Juvet H; Holbrook, N Michele

    2006-09-01

    The stems of large trees serve in transport, storage, and support; however, the degree to which these roles are reflected in their morphology is not always apparent. The large, water-filled stems of baobab trees (Adansonia spp.) are generally assumed to serve a water storage function, yet recent studies indicate limited use of stored water. Through an analysis of wood structure and composition, we examined whether baobab morphology reflects biomechanical constraints rather than water storage capacity in the six Madagascar baobab species. Baobab wood has a high water content (up to 79%), low wood density (0.09-0.17 g · cm(-3)), high parenchyma content (69-88%), and living cells beyond 35 cm into the xylem from the cambium. Volumetric construction cost of the wood is several times lower than in more typical trees, and the elastic modulus approaches that of parenchyma tissue. Safety factors calculated from estimated elastic buckling heights were low, indicating that baobabs are not more overbuilt than other temperate and tropical trees, yet the energy investment in stem material is comparable to that in temperate deciduous trees. Furthermore, the elastic modulus of the wood decreases with water content, such that excessive water withdrawal from the stem could affect mechanical stability.

  8. Deficit irrigation for enhancing sustainable water use: Comparison of cotton nitrogen uptake and prediction of lint yield in a multivariate autoregressive state-space model

    Science.gov (United States)

    Plant adaptation to a limited water supply may be associated with the soil's water holding capacity and landscape features that affect the hydrology. Knowing the response of a crop to water shortage and associated plant water stress symptoms is critical to manage deficit-irrigation, and minimize pla...

  9. Bark beetle-induced tree mortality alters stand energy budgets due to water budget changes

    Science.gov (United States)

    Reed, David E.; Ewers, Brent E.; Pendall, Elise; Frank, John; Kelly, Robert

    2018-01-01

    Insect outbreaks are major disturbances that affect a land area similar to that of forest fires across North America. The recent mountain pine bark beetle ( D endroctonus ponderosae) outbreak and its associated blue stain fungi ( Grosmannia clavigera) are impacting water partitioning processes of forests in the Rocky Mountain region as the spatially heterogeneous disturbance spreads across the landscape. Water cycling may dramatically change due to increasing spatial heterogeneity from uneven mortality. Water and energy storage within trees and soils may also decrease, due to hydraulic failure and mortality caused by blue stain fungi followed by shifts in the water budget. This forest disturbance was unique in comparison to fire or timber harvesting because water fluxes were altered before significant structural change occurred to the canopy. We investigated the impacts of bark beetles on lodgepole pine ( Pinus contorta) stand and ecosystem level hydrologic processes and the resulting vertical and horizontal spatial variability in energy storage. Bark beetle-impacted stands had on average 57 % higher soil moisture, 1.5 °C higher soil temperature, and 0.8 °C higher tree bole temperature over four growing seasons compared to unimpacted stands. Seasonal latent heat flux was highly correlated with soil moisture. Thus, high mortality levels led to an increase in ecosystem level Bowen ratio as sensible heat fluxes increased yearly and latent heat fluxes varied with soil moisture levels. Decline in canopy biomass (leaf, stem, and branch) was not seen, but ground-to-atmosphere longwave radiation flux increased, as the ground surface was a larger component of the longwave radiation. Variability in soil, latent, and sensible heat flux and radiation measurements increased during the disturbance. Accounting for stand level variability in water and energy fluxes will provide a method to quantify potential drivers of ecosystem processes and services as well as lead to greater

  10. Bark beetle-induced tree mortality alters stand energy budgets due to water budget changes

    Science.gov (United States)

    Reed, David E.; Ewers, Brent E.; Pendall, Elise; Frank, John; Kelly, Robert

    2016-10-01

    Insect outbreaks are major disturbances that affect a land area similar to that of forest fires across North America. The recent mountain pine bark beetle (D endroctonus ponderosae) outbreak and its associated blue stain fungi (Grosmannia clavigera) are impacting water partitioning processes of forests in the Rocky Mountain region as the spatially heterogeneous disturbance spreads across the landscape. Water cycling may dramatically change due to increasing spatial heterogeneity from uneven mortality. Water and energy storage within trees and soils may also decrease, due to hydraulic failure and mortality caused by blue stain fungi followed by shifts in the water budget. This forest disturbance was unique in comparison to fire or timber harvesting because water fluxes were altered before significant structural change occurred to the canopy. We investigated the impacts of bark beetles on lodgepole pine (Pinus contorta) stand and ecosystem level hydrologic processes and the resulting vertical and horizontal spatial variability in energy storage. Bark beetle-impacted stands had on average 57 % higher soil moisture, 1.5 °C higher soil temperature, and 0.8 °C higher tree bole temperature over four growing seasons compared to unimpacted stands. Seasonal latent heat flux was highly correlated with soil moisture. Thus, high mortality levels led to an increase in ecosystem level Bowen ratio as sensible heat fluxes increased yearly and latent heat fluxes varied with soil moisture levels. Decline in canopy biomass (leaf, stem, and branch) was not seen, but ground-to-atmosphere longwave radiation flux increased, as the ground surface was a larger component of the longwave radiation. Variability in soil, latent, and sensible heat flux and radiation measurements increased during the disturbance. Accounting for stand level variability in water and energy fluxes will provide a method to quantify potential drivers of ecosystem processes and services as well as lead to greater

  11. Sweet corn water productivity under several deficit irrigation regimes applied during vegetative growth stage using treated wastewater as water irrigation source

    DEFF Research Database (Denmark)

    Hirich, A.; Rami, A.; Laajaj, K.

    2012-01-01

    Yield and Crop Water Productivity are crucial issues in sustainable agriculture, especially in high-demand resource crops such as sweet corn. This study was conducted to investigate agronomic responses such as plant growth, yield and soil parameters (EC and Nitrate accumulation) to several deficit.......4% in terms of dry grain yield, 10.5% in terms of number of ears per plant, 11.5% for the 1000 grains weight and 19% in terms of crop water productivity compared with fully irrigated treatment. While those parameters in addition to root, shoot and plant height has been affected by deficit irrigation during...... vegetative growth stage when increasing water stress degree more than 50% of ETm....

  12. Application of classification-tree methods to identify nitrate sources in ground water.

    Science.gov (United States)

    Spruill, Timothy B; Showers, William J; Howe, Stephen S

    2002-01-01

    A study was conducted to determine if nitrate sources in ground water (fertilizer on crops, fertilizer on golf courses, irrigation spray from hog (Sus scrofa) wastes, and leachate from poultry litter and septic systems) could be classified with 80% or greater success. Two statistical classification-tree models were devised from 48 water samples containing nitrate from five source categories. Model 1 was constructed by evaluating 32 variables and selecting four primary predictor variables (delta 15N, nitrate to ammonia ratio, sodium to potassium ratio, and zinc) to identify nitrate sources. A delta 15N value of nitrate plus potassium > 18.2 indicated animal sources; a value nitrate to ammonia ratio > 575 indicated inorganic fertilizer on agricultural crops; a ratio nitrate from golf courses. A sodium to potassium ratio > 3.2 indicated septic-system wastes; a ratio 2.8 indicated spray wastes from hog lagoons; a value nitrate to ammonia ratio, calcium to magnesium ratio, and sodium to potassium ratio) to distinguish categories. Both models were able to distinguish all five source categories with better than 80% overall success and with 71 to 100% success in individual categories using the learning samples. Seventeen water samples that were not used in model development were tested using Model 2 for three categories, and all were correctly classified. Classification-tree models show great potential in identifying sources of contamination and variables important in the source-identification process.

  13. Three cycles of water deficit from seed to young plants of Moringa oleifera woody species improves stress tolerance.

    Science.gov (United States)

    Rivas, Rebeca; Oliveira, Marciel T; Santos, Mauro G

    2013-02-01

    The main objective of this study was to assess whether recurring water stress occurring from seed germination to young plants of Moringa oleifera Lam. are able to mitigate the drought stress effects. Germination, gas exchange and biochemical parameters were analysed after three cycles of water deficit. Young plants were used 50 days after germination under three osmotic potentials (0.0, -0.3 and -0.4 MPa). For each germination treatment, control (irrigated) and stressed (10% of water control) plants were compared for a total of six treatments. There were two cycles of drought interspersed with 10 days of rehydration. The young plants of M. oleifera showed increased tolerance to repeated cycles of drought, maintaining high relative water content (RWC), high water use efficiency (WUE), increased photosynthetic pigments and increased activity of antioxidant enzymes. There was rapid recovery of the photosynthetic rate during the rehydration period. The stressed plants from the -0.3 and -0.4 MPa treatments showed higher tolerance compared to the control plants. The results suggest that seeds of M. oleifera subjected to mild water deficit have had increased the ability for drought tolerance when young plant. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. The Impact of Precipitation Deficit and Urbanization on Variations in Water Storage in the Beijing-Tianjin-Hebei Urban Agglomeration

    Directory of Open Access Journals (Sweden)

    Zheng Chen

    2017-12-01

    Full Text Available Depletion of water resources has threatened water security in the Beijing-Tianjin-Hebei urban agglomeration, China. However, the relative importance of precipitation and urbanization to water storage change has not been sufficiently studied. In this study, both terrestrial water storage (TWS and groundwater storage (GWS change in Jing-Jin-Ji from 1979 to the 2010s were investigated, based on the global land data assimilation system (GLDAS and the EartH2Observe (E2O outputs, and we used a night light index as an index of urbanization. The results showed that TWS anomaly varied in three stages: significant increase from 1981 to 1996, rapid decrease from 1996 to 2002 and increase from 2002 to the 2010s. Simultaneously, GWS has decreased with about 41.5 cm (500% of GWS in 1979. Both urbanization and precipitation change influenced urban water resource variability. Urbanization was a relatively important factor to the depletion of TWS (explains 83% and GWS (explains 94% since the 1980s and the precipitation deficit explains 72% and 64% of TWS and GWS variabilities. It indicates that urbanization coupled with precipitation deficit has been a more important factor that impacted depletion of both TWS and GWS than climate change only, in the Jing-Jin-Ji region. Moreover, we suggested that the cumulative effect should be considered when discussing the relationship between influence factors and water storage change.

  15. Disentangling the contributions of ontogeny and water stress to photosynthetic limitations in almond trees.

    Science.gov (United States)

    Egea, Gregorio; González-Real, María M; Baille, Alain; Nortes, Pedro A; Diaz-Espejo, Antonio

    2011-06-01

    Very few studies have attempted to disentangle the respective role of ontogeny and water stress on leaf photosynthetic attributes. The relative significance of both effects on photosynthetic attributes has been investigated in leaves of field-grown almond trees [Prunus dulcis (Mill.) D. A. Webb] during four growth cycles. Leaf ontogeny resulted in enhanced leaf dry weight per unit area (W(a)), greater leaf dry-to-fresh weight ratio and lower N content per unit of leaf dry weight (N(w)). Concomitantly, area-based maximum carboxylation rate (V(cmax)), maximum electron transport rate (J(max)), mesophyll conductance to CO₂ diffusion (gm)' and light-saturated net photosynthesis (A(max)) declined in both well-watered and water-stressed almond leaves. Although g(m) and stomatal conductance (g(s)) seemed to be co-ordinated, a much stronger coordination in response to ontogeny and prolonged water stress was observed between g(m) and the leaf photosynthetic capacity. Under unrestricted water supply, the leaf age-related decline of A(max) was equally driven by diffusional and biochemical limitations. Under restricted soil water availability, A(max) was mainly limited by g(s) and, to a lesser extent, by photosynthetic capacity and g(m). When both ontogeny and water stress effects were combined, diffusional limitations was the main determinant of photosynthesis limitation, while stomatal and biochemical limitations contributed similarly. © 2011 Blackwell Publishing Ltd.

  16. Study of Sesame (Sesame indicum L. Cultivars based on Morphological Characteristics Under Water Deficit Stress Condition Using Factor Analysis

    Directory of Open Access Journals (Sweden)

    A Asghari

    2014-03-01

    Full Text Available In order to evaluation sesame cultivars based on morphological characteristics under water deficit stress condition using factor analysis, an experiment was conducted as a split plot based on randomized complete block design with three replications during 2009 in Research Center of Agriculture and Natural Resources in Parsabad. In this experiment, irrigation as the main factor at three levels (50, 75 and 100 percent of crop water requirement and ten sesame cultivars as the sub-factor were studied. The water requirement of sesame was calculated using CROPWAT software (Penman-Monteith method according to FAO-56. Results showed significant differences between the cultivars and the irrigation levels for all studied traits. Interaction between cultivars and irrigation levels was significant for some of traits. Comparisons of means showed that in water deficit condition, yield and all of traits reduced. In all traits the greatest amounts observed in complete irrigation treatment. In 50 percent of water requirement treatment, amount of leaf chlorophyll, root length, root branches and root length/plant height ratio were greater than other treatments. The Karaj1, Ultan, Naze and IS cultivars were better than other cultivars in stress and non stress condition. In factor analysis 5 and 4 first factors in non stress and stress condition explained 91.36 and 89.52 percent of trait variance, respectively. Grouping of sesame cultivars based on first and second factors in non stress conditions showed that Karaj1, Ultan and Naze cultivars were better than other cultivars. Also, in stress conditions Karaj1 and Ultan cultivars grouped as water deficit stress and better cultivars.

  17. Coordination between water transport capacity, biomass growth, metabolic scaling and species stature in co-occurring shrub and tree species.

    Science.gov (United States)

    Smith, Duncan D; Sperry, John S

    2014-12-01

    The significance of xylem function and metabolic scaling theory begins from the idea that water transport is strongly coupled to growth rate. At the same time, coordination of water transport and growth seemingly should differ between plant functional types. We evaluated the relationships between water transport, growth and species stature in six species of co-occurring trees and shrubs. Within species, a strong proportionality between plant hydraulic conductance (K), sap flow (Q) and shoot biomass growth (G) was generally supported. Across species, however, trees grew more for a given K or Q than shrubs, indicating greater growth-based water-use efficiency (WUE) in trees. Trees also showed slower decline in relative growth rate (RGR) than shrubs, equivalent to a steeper G by mass (M) scaling exponent in trees (0.77-0.98). The K and Q by M scaling exponents were common across all species (0.80, 0.82), suggesting that the steeper G scaling in trees reflects a size-dependent increase in their growth-based WUE. The common K and Q by M exponents were statistically consistent with the 0.75 of ideal scaling theory. A model based upon xylem anatomy and branching architecture consistently predicted the observed K by M scaling exponents but only when deviations from ideal symmetric branching were incorporated. © 2014 John Wiley & Sons Ltd.

  18. Retention of stored water enables tropical tree saplings to survive extreme drought conditions.

    Science.gov (United States)

    Wolfe, Brett T

    2017-04-01

    Trees generally maintain a small safety margin between the stem water potential (Ψstem) reached during seasonal droughts and the Ψstem associated with their mortality. This pattern may indicate that species face similar mortality risk during extreme droughts. However, if tree species vary in their ability to regulate Ψstem, then safety margins would poorly predict drought mortality. To explore variation among species in Ψstem regulation, I subjected potted saplings of six tropical tree species to extreme drought and compared their responses with well-watered plants and pretreatment reference plants. In the drought treatment, soil water potential reached Bursera simaruba (L.) Sarg., Cavanillesia platanifolia (Bonpl.) Kunth and Cedrela odorata L. had 100% survival and maintained Ψstem near -1 MPa (i.e., desiccation-avoiding species). Three other species, Cojoba rufescens (Benth.) Britton and Rose, Genipa americana L. and Hymenaea courbaril L. had 50%, 0% and 25% survival, respectively, and survivors had Ψstem <-6 MPa (i.e., desiccation-susceptible species). The desiccation-avoiding species had lower relative water content (RWC) in all organs and tissues (root, stem, bark and xylem) in the drought treatment than in the reference plants (means 72.0-90.4% vs 86.9-97.9%), but the survivors of the desiccation-susceptible C. rufescens had much lower RWC in the drought treatment (44.5-72.1%). Among the reference plants, the desiccation-avoiding species had lower tissue density, leaf-mass fraction and lateral-root surface area (LRA) than the desiccation-susceptible species. Additionally, C. platanifolia and C. odorata had reduced LRA in the drought treatment, which may slow water loss into dry soil. Together, these results suggest that the ability to regulate Ψstem during extreme drought is associated with functional traits that favor retention of stored water and that safety margins during seasonal drought poorly predict survival during extreme drought. © The Author

  19. Soil Moisture/ Tree Water Status Dynamics in Mid-Latitude Montane Forest, Southern Sierra Critical Zone Observatory, CA

    Science.gov (United States)

    Hartsough, P. C.; Malazian, A.; Meadows, M. W.; Roudneva, K.; Storch, J.; Bales, R. C.; Hopmans, J. W.

    2010-12-01

    As part of an effort to understand the root-water-nutrient interactions in the multi-dimensional soil/vegetation system surrounding large trees, in August 2008 we instrumented a mature white fir (Abies concolor) and the surrounding soil to better define the water balance in a single tree. In July 2010, we instrumented a second tree, a Ponderosa pine (Pinus ponderosa) in shallower soils on a drier, exposed slope. The trees are located in a mixed-conifer forest at an elevation of 2000m in the Southern Sierra Critical Zone Observatory. The deployment of more than 250 sensors to measure temperature, volumetric water content, matric potential, and snow depth surrounding the two trees complements sap-flow measurements in the trunk and stem-water-potential measurements in the canopy to capture the seasonal cycles of soil wetting and drying. We show here the results of a multi-year deployment of soil moisture sensors as critical integrators of hydrologic/ biotic interaction in a forested catchment. Sensor networks such as deployed here are a valuable tool in closing the water budget in dynamic forested catchments. While the exchange of energy, water and carbon is continuous, the pertinent fluxes are strongly heterogeneous in both space and time. Thus, the prediction of the behavior of the system across multiple scales constitutes a major challenge.

  20. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil.

    Science.gov (United States)

    Silva, A C; Higuchi, P; van den Berg, E

    2010-08-01

    In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh), total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  1. Effects of soil water table regime on tree community species richness and structure of alluvial forest fragments in Southeast Brazil

    Directory of Open Access Journals (Sweden)

    AC. Silva

    Full Text Available In order to determine the influence of soil water table fluctuation on tree species richness and structure of alluvial forest fragments, 24 plots were allocated in a point bar forest and 30 plots in five forest fragments located in a floodplain, in the municipality of São Sebastião da Bela Vista, Southeast Brazil, totalizing 54, 10 X 20 m, plots. The information recorded in each plot were the soil water table level, diameter at breast height (dbh, total height and botanical identity off all trees with dbh > 5 cm. The water table fluctuation was assessed through 1 m deep observation wells in each plot. Correlations analysis indicated that sites with shallower water table in the flooding plains had a low number of tree species and high tree density. Although the water table in the point bar remained below the wells during the study period, low tree species richness was observed. There are other events taking place within the point bar forest that assume a high ecological importance, such as the intensive water velocity during flooding and sedimentation processes.

  2. Tree water potentials supporting an explanation for the occurrence of Vachellia erioloba in the Namib Desert (Namibia)

    OpenAIRE

    Joachim H. A. Krug

    2017-01-01

    Background Site-vegetation relations of Vachellia erioloba, Faidherbia albida, Euclea pseudebenus and Tamarix usneoides in two contrasting locations in the Namib Desert (Namibia) were evaluated with the goal to relate soil water availability to the occurrence of trees under hyper-arid conditions. Methods Plant water potentials were measured using a pressure chamber in the field. Pre-dawn water potentials were assessed to reflect the soil water potential of the rhizosphere. Midday wa...

  3. Effects of deficit drip-irrigation scheduling regimes with saline water on pepper yield, water productivity and soil salinity under arid conditions of Tunisia

    Directory of Open Access Journals (Sweden)

    Kamel Nagaz

    2012-12-01

    Full Text Available A two-year study was carried out in order to assess the effects of different irrigation scheduling regimes with saline water on soil salinity, yield and water productivity of pepper under actual commercial-farming conditions in the arid region of Tunisia. Pepper was grown on a sandy soil and drip-irrigated with water having an ECi of 3.6 dS/m. Irrigation treatments consisted in water replacements of accumulated ETc at levels of 100% (FI, full irrigation, 80% (DI-80, 60% (DI-60, when the readily available water in the control treatment (FI is depleted, deficit irrigation during ripening stage (FI-MDI60 and farmer method corresponding to irrigation practices implemented by the local farmers (FM. Results on pepper yield and soil salinity are globally consistent between the two-year experiments and shows significant difference between irrigation regimes. Higher soil salinity was maintained over the two seasons, 2008 and 2009, with DI-60 and FM treatments than FI. FI-MDI60 and DI-80 treatments resulted also in low ECe values. Highest yields for both years were obtained under FI (22.3 and 24.4 t/ha although we didn’t find significant differences with the regulated deficit irrigation treatment (FI-DI60. However, the DI-80 and DI-60 treatments caused significant reductions in pepper yields through a reduction in fruits number/m² and average fruit weight in comparison with FI treatment. The FM increased soil salinity and caused significant reductions in yield with 14 to 43%, 12 to 39% more irrigation water use than FI, FI-MDI60 and DI-80 treatments, respectively, in 2008 and 2009. Yields for all irrigation treatments were higher in the second year compared to the first year. Water productivity (WP values reflected this difference and varied between 2.31 and 5.49 kg/m3. The WP was found to vary significantly among treatments, where the highest and the lowest values were observed for DI-60 treatment and FM, respectively. FI treatment provides

  4. Is Change in Ovary Carbon Status a Cause or a Consequence of Maize Ovary Abortion in Water Deficit during Flowering?

    Science.gov (United States)

    Oury, Vincent; Caldeira, Cecilio F; Prodhomme, Duyên; Pichon, Jean-Philippe; Gibon, Yves; Tardieu, François; Turc, Olivier

    2016-06-01

    Flower or grain abortion causes large yield losses under water deficit. In maize (Zea mays), it is often attributed to a carbon limitation via the disruption of sucrose cleavage by cell wall invertases in developing ovaries. We have tested this hypothesis versus another linked to the expansive growth of ovaries and silks. We have measured, in silks and ovaries of well-watered or moderately droughted plants, the transcript abundances of genes involved in either tissue expansion or sugar metabolism, together with the concentrations and amounts of sugars, and with the activities of major enzymes of carbon metabolism. Photosynthesis and indicators of sugar export, measured during water deprivation, suggested sugar export maintained by the leaf. The first molecular changes occurred in silks rather than in ovaries and involved genes affecting expansive growth rather than sugar metabolism. Changes in the concentrations and amounts of sugars and in the activities of enzymes of sugar metabolism occurred in apical ovaries that eventually aborted, but probably after the switch to abortion of these ovaries. Hence, we propose that, under moderate water deficits corresponding to most European drought scenarios, changes in carbon metabolism during flowering time are a consequence rather than a cause of the beginning of ovary abortion. A carbon-driven ovary abortion may occur later in the cycle in the case of carbon shortage or under very severe water deficits. These findings support the view that, until the end of silking, expansive growth of reproductive organs is the primary event leading to abortion, rather than a disruption of carbon metabolism. © 2016 American Society of Plant Biologists. All Rights Reserved.

  5. New ABA-Hypersensitive Arabidopsis Mutants Are Affected in Loci Mediating Responses to Water Deficit and Dickeya dadantii Infection

    Science.gov (United States)

    Plessis, Anne; Cournol, Raphaël; Effroy, Delphine; Silva Pérez, Viridiana; Botran, Lucy; Kraepiel, Yvan; Frey, Anne; Sotta, Bruno; Cornic, Gabriel; Leung, Jeffrey; Giraudat, Jérôme; Marion-Poll, Annie; North, Helen M.

    2011-01-01

    On water deficit, abscisic acid (ABA) induces stomata closure to reduce water loss by transpiration. To identify Arabidopsis thaliana mutants which transpire less on drought, infrared thermal imaging of leaf temperature has been used to screen for suppressors of an ABA-deficient mutant (aba3-1) cold-leaf phenotype. Three novel mutants, called hot ABA-deficiency suppressor (has), have been identified with hot-leaf phenotypes in the absence of the aba3 mutation. The defective genes imparted no apparent modification to ABA production on water deficit, were inherited recessively and enhanced ABA responses indicating that the proteins encoded are negative regulators of ABA signalling. All three mutants showed ABA-hypersensitive stomata closure and inhibition of root elongation with little modification of growth and development in non-stressed conditions. The has2 mutant also exhibited increased germination inhibition by ABA, while ABA-inducible gene expression was not modified on dehydration, indicating the mutated gene affects early ABA-signalling responses that do not modify transcript levels. In contrast, weak ABA-hypersensitivity relative to mutant developmental phenotypes suggests that HAS3 regulates drought responses by both ABA-dependent and independent pathways. has1 mutant phenotypes were only apparent on stress or ABA treatments, and included reduced water loss on rapid dehydration. The HAS1 locus thus has the required characteristics for a targeted approach to improving resistance to water deficit. In contrast to has2, has1 exhibited only minor changes in susceptibility to Dickeya dadantii despite similar ABA-hypersensitivity, indicating that crosstalk between ABA responses to this pathogen and drought stress can occur through more than one point in the signalling pathway. PMID:21633512

  6. Comparative studies using the Morris water maze to assess spatial memory deficits in two transgenic mouse models of Alzheimer's disease.

    Science.gov (United States)

    Edwards, Stephen R; Hamlin, Adam S; Marks, Nicola; Coulson, Elizabeth J; Smith, Maree T

    2014-10-01

    Evaluation of the efficacy of novel therapeutics for potential treatment of Alzheimer's disease (AD) requires an animal model that develops age-related cognitive deficits reproducibly between independent groups of investigators. Herein we assessed comparative temporal changes in spatial memory function in two commercially available transgenic mouse models of AD using the Morris water maze (MWM), incorporating both visible and hidden platform training. Individual cohorts of cDNA-based 'line 85'-derived double-transgenic mice coexpressing the 'Swedish' mutation of amyloid precursor protein (APPSwe) and the presenillin 1 (PS1) 'dE9' mutation were assessed in the MWM at mean ages of 3.6, 9.3 and 14.8 months. We found significant deficits in spatial memory retention in APPSwe/PS1dE9 mice aged 3.6 months and robust deficits in spatial memory acquisition and retention in APPSwe/PS1dE9 mice aged 9.3 months, with a further significant decline by age 14.8 months. β-Amyloid deposits were present in brain sections by 7.25 months of age. In contrast, MWM studies with individual cohorts (aged 4-21 months) of single-transgenic genomic-based APPSwe mice expressing APPSwe on a yeast artificial chromosomal (YAC) construct showed no significant deficits in spatial memory acquisition until 21 months of age. There were no significant deficits in spatial memory retention up to 21 months of age and β-amyloid deposits were not present in brain sections up to 24 months of age. These data, generated using comprehensive study designs, show that APPSwe/PS1dE9 but not APPSwe YAC mice appear to provide a suitably robust model of AD for efficacy assessment of novel AD treatments in development. © 2014 Wiley Publishing Asia Pty Ltd.

  7. Type 3 metallothioneins respond to water deficit in leaf and in the cambial zone of white poplar (Populus alba).

    Science.gov (United States)

    Berta, Monica; Giovannelli, Alessio; Potenza, Emilio; Traversi, Maria Laura; Racchi, Milvia Luisa

    2009-03-15

    The involvement of metallothioneins (MTs) in response to plant water stress and recovery was assessed by analyzing gene expression in leaves and in the cambial zone of white poplar. One-year-old plants were submitted to two different watering regimes: irrigation was withheld for 9d and then resumed until day 17, or soil moisture was maintained to field capacity by irrigation during the experiment. Changes in leaves and stem water relations, gas exchange and CO(2) assimilation were recorded. The expression profiles of MT genes were analyzed in developing leaves and the cambial zone at maximum stress levels and after recovery and compared with the watered controls. Whole-plant water relations were significantly affected by water deprivation, though a complete recovery of plant water status was reached after resumption of watering. Withholding irrigation resulted in a significant decrease of leaf turgor potential and relative water content without a significant increase of the osmotic potential at full turgor. Similarly, stem water content decreased, leading to a marked increase of stem shrinkage, confirming that mild water stress affected primarily tissue water status. Following water depletion, the transcript analysis of MT genes revealed increased expression of type 3a and 3b MT genes in cambial tissues, and particularly in leaves. After water resumption, transcription decreased, suggesting that the changes in gene expression were related to water deficit. The results indicate that in leaves and, for the first time, in the cambial zone, type 3 MTs respond in a specific manner to changes in water status. These results are consistent with the regulatory cis-elements present in the 5' flanking region of type 3 MT genes.

  8. Changes of leaf water potential and endogenous cytokinins in young apple trees treated with or without paclobutrazol under drought conditions

    NARCIS (Netherlands)

    Zhu, L.; Peppel, van de A.C.; Li, X.; Welander, M.

    2004-01-01

    Leaf water potential and endogenous cytokinins in xylem sap of young apple trees treated with or without paclobutrazol (PBZ) under drought stress conditions were investigated. Three drought and rewatering cycles were used in the experiments and leaf water potential was measured every 2-4 days during

  9. Native trees show conservative water use relative to invasive: results from a removal experiment in a Hawaiian wet forest

    Science.gov (United States)

    M.A. Cavaleri; R. Ostertag; S. Cordell; L. and Sack

    2014-01-01

    While the supply of freshwater is expected to decline in many regions in the coming decades, invasive plant species, often 'high water spenders', are greatly expanding their ranges worldwide. In this study, we quantified the ecohydrological differences between native and invasive trees and also the effects of woody invasive removal on plot-level water use in...

  10. Extreme Drought Event and Shrub Invasion Reduce Oak Trees Functioning and Resilience on Water-Limited Ecosystems

    Science.gov (United States)

    Caldeira, M. C.; Lobo-do-Vale, R.; Lecomte, X.; David, T. S.; Pinto, J. G.; Bugalho, M. N.; Werner, C.

    2016-12-01

    Extreme droughts and plant invasions are major drivers of global change that can critically affect ecosystem functioning. Shrub encroachment is increasing in many regions worldwide and extreme events are projected to increase in frequency and intensity, namely in the Mediterranean region. Nevertheless, little is known about how these drivers may interact and affect ecosystem functioning and resilience Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event in a Mediterranean oak woodland, we show that the combination of native shrub invasion and extreme drought reduced ecosystem transpiration and the resilience of the key-stone oak tree species. We established six 25 x 25 m paired plots in a shrub (Cistus ladanifer L.) encroached Mediterranean cork-oak (Quercus suber L.) woodland. We measured sapflow and pre-dawn leaf water potential of trees and shrubs and soil water content in all plots during four years. We determined the resilience of tree transpiration to evaluate to what extent trees recovered from the extreme drought event. From February to November 2011 we conducted baseline measurements for plot comparison. In November 2011 all the shrubs from one of all the paired plots were cut and removed. Ecosystem transpiration was dominated by the water use of the invasive shrub, which further increased after the extreme drought. Simultaneously, tree transpiration in invaded plots declined more sharply (67 ± 13 %) than in plots cleared from shrubs (31 ± 11%) relative to the pre-drought year (2011). Trees in invaded plots were not able to recover in the following wetter year showing lower resilience to the extreme drought event. Our results imply that in Mediterranean-type of climates invasion by water spending species coupled with the projected recurrent extreme droughts will cause critical drought tolerance thresholds of trees to be overcome, thus increasing the probability of tree mortality.

  11. Effect of Azofert®on the yield of common bean varieties (Phaseolus vulgaris L.)under conditions of water deficit

    OpenAIRE

    Wilfredo Estrada Prado; Licet Chávez Suárez; Eduardo Jerez Mompie; María Caridad Nápoles García; Ariel Sosa Rodríguez; Cristóbal Cordoví Dominguez; Fernando Celeiro Rodríguez

    2017-01-01

    The effect of Azofert® on the induction of tolerance of bean varieties to water deficit was evaluated. The experiment was developed during the period 2013-2014 at the Cooperative for Credits and Services Strengthened "Roberto Aguilar", Bayamo municipality, Granma, Cuba. Varieties CC-25-9R and Tomeguín-93 were used, which were applied four treatments, consisting of normal irrigation conditions throughout the crop cycle and conditions of water deficit at the beginning of flowering, formation an...

  12. Genetic variability for leaf growth rate and duration under water deficit in sunflower: analysis of responses at cell, organ, and plant level.

    Science.gov (United States)

    Pereyra-Irujo, Gustavo A; Velázquez, Luciano; Lechner, Leandra; Aguirrezábal, Luis A N

    2008-01-01

    Plants under water deficit reduce leaf growth, thereby reducing transpiration rate at the expense of reduced photosynthesis. The objective of this work was to analyse the response of leaf growth to water deficit in several sunflower genotypes in order to identify and quantitatively describe sources of genetic variability for this trait that could be used to develop crop varieties adapted to specific scenarios. The genetic variability of the response of leaf growth to water deficit was assessed among 18 sunflower (Helianthus annuus L.) inbred lines representing a broad range of genetic diversity. Plants were subjected to long-term, constant-level, water-deficit treatments, and the response to water deficit quantified by means of growth models at cell-, leaf-, and plant-scale. Significant variation among lines was found for the response of leaf expansion rate and of leaf growth duration, with an equal contribution of these responses to the variability in the reduction of leaf area. Increased leaf growth duration under water deficit is usually suggested to be caused by changes in the activity of cell-wall enzymes, but the present results suggest that the duration of epidermal cell division plays a key role in this response. Intrinsic genotypic responses of rate and duration at a cellular scale were linked to genotypic differences in whole-plant leaf area profile to water deficit. The results suggest that rate and duration responses are the result of different physiological mechanisms, and therefore capable of being combined to increase the variability in leaf area response to water deficit.

  13. Identification of drought-response genes and a study of their expression during sucrose accumulation and water deficit in sugarcane culms

    Directory of Open Access Journals (Sweden)

    Xu Jingsheng

    2011-01-01

    Full Text Available Abstract Background The ability of sugarcane to accumulate high concentrations of sucrose in its culm requires adaptation to maintain cellular function under the high solute load. We have investigated the expression of 51 genes implicated in abiotic stress to determine their expression in the context of sucrose accumulation by studying mature and immature culm internodes of a high sucrose accumulating sugarcane cultivar. Using a sub-set of eight genes, expression was examined in mature internode tissues of sugarcane cultivars as well as ancestral and more widely related species with a range of sucrose contents. Expression of these genes was also analysed in internode tissue from a high sucrose cultivar undergoing water deficit stress to compare effects of sucrose accumulation and water deficit. Results A sub-set of stress-related genes that are potentially associated with sucrose accumulation in sugarcane culms was identified through correlation analysis, and these included genes encoding enzymes involved in amino acid metabolism, a sugar transporter and a transcription factor. Subsequent analysis of the expression of these stress-response genes in sugarcane plants that were under water deficit stress revealed a different transcriptional profile to that which correlated with sucrose accumulation. For example, genes with homology to late embryogenesis abundant-related proteins and dehydrin were strongly induced under water deficit but this did not correlate with sucrose content. The expression of genes encoding proline biosynthesis was associated with both sucrose accumulation and water deficit, but amino acid analysis indicated that proline was negatively correlated with sucrose concentration, and whilst total amino acid concentrations increased about seven-fold under water deficit, the relatively low concentration of proline suggested that it had no osmoprotectant role in sugarcane culms. Conclusions The results show that while there was a

  14. Effects of soil water deficits on three genotypes of potted Campanula medium plants during bud formation stage

    DEFF Research Database (Denmark)

    Mao, Hongyu; Sun, Yanqi; Müller, Renate

    2014-01-01

    Potted ornamental plants are often exposed to drought stress during shipping and retailing, which decreases the value and postharvest quality. Thus, selection of genotypes which can better withstand soil water deficits is essential for sustainable production. Here, the response of three genotypes...... of potted Campanula medium (denoted as G100, G102 and G104) to progressive soil drying was investigated and their post-production performance was evaluated for four weeks. The potted plants were grown in a climate controlled greenhouse and were either well-watered (W) or drought-stressed (D) at floral bud...... of T in G100 would allow the plant to conserve water in the soil; however, owing to its putative larger leaf area and greater stomatal density on the adaxial leaf surface, G100 quickly depleted soil water and resulted in severe drought stress to the plants as exemplified by the significantly lowered gs...

  15. Seasonality of Leaf and Fig Production in Ficus squamosa, a Fig Tree with Seeds Dispersed by Water.

    Directory of Open Access Journals (Sweden)

    Pornwiwan Pothasin

    Full Text Available The phenology of plants reflects selection generated by seasonal climatic factors and interactions with other plants and animals, within constraints imposed by their phylogenetic history. Fig trees (Ficus need to produce figs year-round to support their short-lived fig wasp pollinators, but this requirement is partially de-coupled in dioecious species, where female trees only develop seeds, not pollinator offspring. This allows female trees to concentrate seed production at more favorable times of the year. Ficus squamosa is a riparian species whose dispersal is mainly by water, rather than animals. Seeds can float and travel in long distances. We recorded the leaf and reproductive phenology of 174 individuals for three years in Chiang Mai, Northern Thailand. New leaves were produced throughout the year. Fig production occurred year-round, but with large seasonal variations that correlated with temperature and rainfall. Female and male trees initiated maximal fig crops at different times, with production in female trees confined mainly to the rainy season and male figs concentrating fig production in the preceding months, but also often bearing figs continually. Ficus squamosa concentrates seed production by female plants at times when water levels are high, favouring dispersal by water, and asynchronous flowering within male trees allow fig wasps to cycle there, providing them with potential benefits by maintaining pollinators for times when female figs become available to pollinate.

  16. Seasonality of Leaf and Fig Production in Ficus squamosa, a Fig Tree with Seeds Dispersed by Water.

    Science.gov (United States)

    Pothasin, Pornwiwan; Compton, Stephen G; Wangpakapattanawong, Prasit

    2016-01-01

    The phenology of plants reflects selection generated by seasonal climatic factors and interactions with other plants and animals, within constraints imposed by their phylogenetic history. Fig trees (Ficus) need to produce figs year-round to support their short-lived fig wasp pollinators, but this requirement is partially de-coupled in dioecious species, where female trees only develop seeds, not pollinator offspring. This allows female trees to concentrate seed production at more favorable times of the year. Ficus squamosa is a riparian species whose dispersal is mainly by water, rather than animals. Seeds can float and travel in long distances. We recorded the leaf and reproductive phenology of 174 individuals for three years in Chiang Mai, Northern Thailand. New leaves were produced throughout the year. Fig production occurred year-round, but with large seasonal variations that correlated with temperature and rainfall. Female and male trees initiated maximal fig crops at different times, with production in female trees confined mainly to the rainy season and male figs concentrating fig production in the preceding months, but also often bearing figs continually. Ficus squamosa concentrates seed production by female plants at times when water levels are high, favouring dispersal by water, and asynchronous flowering within male trees allow fig wasps to cycle there, providing them with potential benefits by maintaining pollinators for times when female figs become available to pollinate.

  17. Water deficit improved the capacity of arbuscular mycorrhizal fungi (AMF) for inducing the accumulation of antioxidant compounds in lettuce leaves.

    Science.gov (United States)

    Baslam, Marouane; Goicoechea, Nieves

    2012-07-01

    Lettuce, a major food crop within the European Union and the most used for the so-called 'Fourth Range' of vegetables, can associate with arbuscular mycorrhizal fungi (AMF). Mycorrhizal symbiosis can stimulate the synthesis of secondary metabolites, which may increase plant tolerance to stresses and enhance the accumulation of antioxidant compounds potentially beneficial to human health. Our objectives were to assess (1) if the application of a commercial formulation of AMF benefited growth of lettuce under different types and degrees of water deficits; (2) if water restrictions affected the nutritional quality of lettuce; and (3) if AMF improved the quality of lettuce when plants grew under reduced irrigation. Two cultivars of lettuce consumed as salads, Batavia Rubia Munguía and Maravilla de Verano, were used in the study. Four different water regimes were applied to both non-mycorrhizal and mycorrhizal plants: optimal irrigation (field capacity [FC]), a water regime equivalent to 2/3 of FC, a water regime equivalent to 1/2 of FC and a cyclic drought (CD). Results showed that mycorrhizal symbiosis improved the accumulation of antioxidant compounds, mainly carotenoids and anthocyanins, and to a lesser extent chlorophylls and phenolics, in leaves of lettuce. These enhancements were higher under water deficit than under optimal irrigation. Moreover, shoot biomass in mycorrhizal lettuces subjected to 2/3 of FC were similar to those of non-mycorrhizal plants cultivated under well-watered conditions. In addition, lettuces subjected to 2/3 FC had similar leaf RWC than their respective well-watered controls, regardless of mycorrhizal inoculation. Therefore, results suggest that mycorrhizal symbiosis can improve quality of lettuce and may allow restrict irrigation without reducing production.

  18. Membrane Proteins Are Dramatically Less Conserved than Water-Soluble Proteins across the Tree of Life.

    Science.gov (United States)

    Sojo, Victor; Dessimoz, Christophe; Pomiankowski, Andrew; Lane, Nick

    2016-11-01

    Membrane proteins are crucial in transport, signaling, bioenergetics, catalysis, and as drug targets. Here, we show that membrane proteins have dramatically fewer detectable orthologs than water-soluble proteins, less than half in most species analyzed. This sparse distribution could reflect rapid divergence or gene loss. We find that both mechanisms operate. First, membrane proteins evolve faster than water-soluble proteins, particularly in their exterior-facing portions. Second, we demonstrate that predicted ancestral membrane proteins are preferentially lost compared with water-soluble proteins in closely related species of archaea and bacteria. These patterns are consistent across the whole tree of life, and in each of the three domains of archaea, bacteria, and eukaryotes. Our findings point to a fundamental evolutionary principle: membrane proteins evolve faster due to stronger adaptive selection in changing environments, whereas cytosolic proteins are under more stringent purifying selection in the homeostatic interior of the cell. This effect should be strongest in prokaryotes, weaker in unicellular eukaryotes (with intracellular membranes), and weakest in multicellular eukaryotes (with extracellular homeostasis). We demonstrate that this is indeed the case. Similarly, we show that extracellular water-soluble proteins exhibit an even stronger pattern of low homology than membrane proteins. These striking differences in conservation of membrane proteins versus water-soluble proteins have important implications for evolution and medicine. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Synergistic use of biochar, compost and plant growth-promoting rhizobacteria for enhancing cucumber growth under water deficit conditions.

    Science.gov (United States)

    Nadeem, Sajid M; Imran, Muhammad; Naveed, Muhammad; Khan, Muhammad Y; Ahmad, Maqshoof; Zahir, Zahir A; Crowley, David E

    2017-12-01

    Limited information is available about the effectiveness of biochar with plant growth-promoting rhizobacteria (PGPR) and compost. A greenhouse study was conducted to evaluate the effect of biochar in combination with compost and PGPR (Pseudomonas fluorescens) for alleviating water deficit stress. Both inoculated and un-inoculated cucumber seeds were sown in soil treated with biochar, compost and biochar + compost. Three water levels - field capacity (D0), 75% field capacity (D1) and 50% field capacity (D2) - were maintained. The results showed that water deficit stress significantly suppressed the growth of cucumber; however, synergistic use of biochar, compost and PGPR mitigated the negative impact of stress. At D2, the synergistic use of biochar, compost and PGPR caused significant increases in shoot length, shoot biomass, root length and root biomass, which were respectively 88, 77, 89 and 74% more than in the un-inoculated control. Significant improvements in chlorophyll and relative water contents as well as reduction in leaf electrolyte leakage demonstrated the effectiveness of this approach. Moreover, the highest population of P. fluorescens was observed where biochar and compost were applied together. These results suggest that application of biochar with PGPR and/or compost could be an effective strategy for enhancing plant growth under stress. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Patterns of leaf conductance and water potential of five Himalayan tree species.

    Science.gov (United States)

    Poudyal, K; Jha, P K; Zobel, D B; Thapa, C B

    2004-06-01

    We studied variations in water relations and drought response in five Himalayan tree species (Schima wallichii (DC.) Korth. (chilaune) and Castanopsis indica (Roxb.) Miq. (dhale katus) at an elevation of 1400 m, Quercus lanata Smith (banjh) and Rhododendron arboreum Smith (lali gurans) at 2020 m, and Quercus semecarpifolia Smith (khasru) at 2130 m) at Phulchowki Hill, Kathmandu, Nepal. Soil water potential at 15 (Psi(s15)) and 30 cm (Psi(s30)) depths, tree water potential at predawn (Psi(pd)) and midday (Psi(md)), and leaf conductance during the morning (g(wAM)) and afternoon (g(wPM)) were observed from December 1998 to April 2001, except during the monsoon months. There was significant variation among sites, species and months in Psi(pd), Psi(md), g(wAM) and g(wPM), and among months for all species for Psi(s15). Mean Psi(pd) and Psi(md) were lowest in Q. semecarpifolia (-0.40 and -1.18 MPa, respectively) and highest in S. wallichii (-0.20 and -0.63 MPa, respectively). The minimum Psi value for all species (-0.70 to -1.79 MPa) was observed in March 1999, after 4 months of unusually low rainfall. Some patterns of Psi(pd) were related to phenology and leaf damage. During leafing, Psi(pd) often increased. Mean g(wAM) and g(wPM) were highest in Q. semecarpifolia (172 and 190 mmol m(-2) s(-1), respectively) and lowest in C. indica (78 and 74 mmol m(-2) s(-1), respectively). Soil water potential (Psi) at 15 cm depth correlated with plant Psi in all species, but rarely with g(wAM) and not with g(wPM). Plant Psi declined with increasing elevation, whereas g(w) increased. As Psi(pd) declined, so did maximal g(w), but overall, g(w) was correlated with Psi(pd) only for R. arboreum. Schima wallichii maintained high Psi, with low stomatal conductance, as did Castanopsis indica, except that C. indica had low Psi during dry months. Rhododendron arboreum maintained high Psi(pd) and g(w), despite low soil Psi. Quercus lanata had low g(w) and low Psi(pd) in some months, but showed

  1. Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.

    Science.gov (United States)

    Smiljanić, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Stajić, Branko; Wilmking, Martin

    2014-12-01

    Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Transpiration by trees under seasonal water logging and drought in monsoon central Cambodia

    Science.gov (United States)

    Miyazawa, Y.; Tateishi, M.; Kajisa, T.; Ma, V.; Heng, S.; Kumagai, T.; Mizoue, N.

    2012-04-01

    Cambodia is situated in the center of Indochina Peninsula and experiences severe drought for 5 months of dry season and subsequent rainy season. Around the Tonlesap Lake where both natural and secondary forests exist without intensive destruction by human activity, forest hydrology is characterized by seasonal water logging in mid rainy season. Tree- and stand-scale transpiration is thought to be influenced by the changing soil water conditions and trees' site-specific adaptation to the environment, but less is measured about transpiration and leaf ecophysiological traits in this region. The objectives of this study is to reveal the ecophysiology of the two native (Dipterocarpus obtusifolius and Shorea roxburghii) and two exotic species (Acacia auriculiformis and Eucalyptus camaldulensis) and to detect the effects of soil water conditions on day to week scale transpiration in mid rainy and dry season. Seasonal leaf-level photosynthesis measurements suggested that photosynthetic capacity (Vcmax25) showed no clear seasonal change in each species without clear interspecific variation. Two native species had stomatal control in response to the environment different from previous studies and showed stomatal conductance higher than most woody species in other seasonal tropical forests, suggesting the species- and site-specific adaptation to the easy access to the ground water. Sap flow rate per leaf area was expressed in two parameters: measured transpiration rate based on the continuous sap flow measurements (Esap) and modeled transpiration rate (Emod) using a multilayer model based on the measured data of atmospheric environments, radiation and the leaf ecophysiological traits. Esap was lower in rainy season than those in dry season, with short but pronounced drop near the end of the dry season, although Emod was higher in rainy season than in dry season. In dry season, Emod well fit the diurnal and day to day trend of Esap, suggesting that soil drought did not limit

  3. Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork-oak woodland

    Science.gov (United States)

    Dubbert, Maren; Mosena, Alexander; Piayda, Arndt; Cuntz, Matthias; Correia, Alexandra Cristina; Pereira, Joao Santos; Werner, Christiane

    2014-08-01

    Facilitation and competition between different vegetation layers may have a large impact on small-scale vegetation development. We propose that this should not only influence overall herbaceous layer yield but also species distribution and understory longevity, and hence the ecosystems carbon uptake capacity especially during spring. We analyzed the effects of trees on microclimate and soil properties (water and nitrate content) as well as the development of an herbaceous community layer regarding species composition, aboveground biomass and net water and carbon fluxes in a cork-oak woodland in Portugal, between April and November 2011. The presence of trees caused a significant reduction in photosynthetic active radiation of 35 mol m-2 d-1 and in soil temperature of 5 °C from April to October. At the same time differences in species composition between experimental plots located in open areas and directly below trees could be observed: species composition and abundance of functional groups became increasingly different between locations from mid April onwards. During late spring drought adapted native forbs had significantly higher cover and biomass in the open area while cover and biomass of grasses and nitrogen fixing forbs was highest under the trees. Further, evapotranspiration and net carbon exchange decreased significantly stronger under the tree crowns compared to the open during late spring and the die back of herbaceous plants occurred earlier and faster under trees. This was most likely caused by interspecific competition for water between trees and herbaceous plants, despite the more favorable microclimate conditions under the trees during the onset of summer drought.

  4. Tropical tree water use under seasonal waterlogging and drought in central Cambodia

    Science.gov (United States)

    Miyazawa, Yoshiyuki; Tateishi, Makiko; Komatsu, Hikaru; Ma, Vuthy; Kajisa, Tsuyoshi; Sokh, Heng; Mizoue, Nobuya; Kumagai, Tomo'omi

    2014-07-01

    In central Cambodia, rapid growing non-endemic species are planted for future timber production. However, less is understood about the impact of the introduction of non-endemic species on the transpiration characteristics of the forest, which has been composed of native species that adapted to the highly seasonal environments. Sap flux of two native and one non-endemic tree species in central Cambodia was measured to reveal its seasonal trends and variability in the Monsoon Asia region. Measurements were carried out in a 10- to 15-year-old forest in the dry and rainy seasons that were defined by differing rainfall patterns. The seasonal trend in depth to water table differed from that of rainfall; groundwater table depth reached zero late in the rainy season and increased gradually after the onset of the dry season. The ratio of sap flux to an equilibrium evaporation condition of the native species, Popel (Shorea roxburghii), showed a sharp decline at the end of the dry season, whereas that of a non-endemic species, eucalyptus (Eucalyptus camaldulensis), decreased in the mid rainy season while Tbeng (Dipterocarpus obtusifolius) did not show a clear trend. The ratio of sap flux to an equilibrium evaporation was negatively correlated with the depth to water table in Popel, but was positively correlated in eucalyptus, possibly because of the negative effects of flooding. In addition to the large seasonal variation, intra-species variation in sap flux was also large and was a major controlling factor for tree-level water uptake at this young forest site in both dry and rainy seasons. In conclusion, the transpiration characteristics of this forest were species-specific and were controlled more by the fluctuating depths to groundwater rather than the onset of the rainy/dry seasons defined by rainfall events.

  5. ESTABLISHMENT OF YOUNG “DWARF GREEN” COCONUT PLANTS IN SOIL AFFECTED BY SALTS AND UNDER WATER DEFICIT

    Directory of Open Access Journals (Sweden)

    ALEXANDRE REUBER ALMEIDA DA SILVA

    Full Text Available ABSTRACT The aim was to analyze the establishment of young “Green Dwarf” coconut plants in soils affected by salts and under water stress, by evaluating leaf area, biomass production and allocation. In the experiment, conducted in protected environment in Fortaleza, CE, in statistical design of randomized blocks in a split plot arrangement, the effects of different water deficit levels (plots were evaluated, by imposing different percentages of replacement of water losses by potential crop evapotranspiration - ETpc (20, 40, 60, 80 and 100%, associated with subplots consisting of increasing soil salinity levels (1.72, 6.25, 25.80 and 40.70 dS m-1 provided by soil collected at different parts of the Morada Nova Irrigated Perimeter - PIMN. Leaf area and biomass production were sharply reduced by the conditions of water stress and high soil salinity, apparently being more critical to the crop under water restriction condition. The degree of water stress can increase the susceptibility to salinity and plants can be considered, in general terms, as moderately tolerant to the effects of salinity, when combined with water deficiency. Coconut seedlings show full capacity of establishment in PIMN saline soils, corresponding to the level of electrical conductivity of 6.50 dS m-1, but only when the water supply remains adequate. For higher salinity levels, plants survive, but their size is reduced by around 50%, even when fully irrigated.

  6. Elevated CO2 increases tree-level intrinsic water use efficiency: insights from carbon and oxygen isotope analyses in tree rings across three forest FACE sites

    Energy Technology Data Exchange (ETDEWEB)

    Battipaglia, Giovanna [Second University of Naples; Saurer, Matthias [Paul Scherrer Institut, Villigen, Switzerland; Cherubini, Paulo [WSL Swiss Federal Institute for Forest, Snow and Landscape Research; Califapietra, Carlo [University of Tuscia; McCarthy, Heather R [Duke University; Norby, Richard J [ORNL; Cotrufo, M. Francesca [Colorado State University, Fort Collins

    2013-01-01

    Elevated CO2 increases intrinsic water use efficiency (WUEi) of forests, but the magnitude of this effect and its interaction with climate is still poorly understood. We combined tree ring analysis with isotope measurements at three Free Air CO2 Enrichment (FACE, POP-EUROFACE, in Italy; Duke FACE in North Carolina and ORNL in Tennessee, USA) sites, to cover the entire life of the trees. We used 13C to assess carbon isotope discrimination ( 13C ci/ca) and changes in WUEi, while direct CO2 effects on stomatal conductance were explored using 18O as a proxy. Across all the sites, elevated CO2 increased 13C-derived WUEi on average by 73% for Liquidambar styraciflua, 77% for Pinus taeda and 75% for Populus sp., but through different ecophysiological mechanisms. Our findings provide a robust means of predicting WUEi responses from a variety of tree species exposed to variable environmental conditions over time, and species-specific relationships that can help modeling elevated CO2 and climate impacts on forest productivity, carbon and water balances.

  7. Supplemental selenium improves wheat grain yield and quality through alterations in biochemical processes under normal and water deficit conditions.

    Science.gov (United States)

    Nawaz, Fahim; Ashraf, M Y; Ahmad, R; Waraich, E A; Shabbir, R N; Bukhari, M A

    2015-05-15

    The paper mainly reported the effects of exogenous selenium (Se) supply (Se seed priming, Se fertigation and Se foliar spray) on physiological and antioxidant system of wheat aiming to clarify its effect on yield and nutritional quality of wheat under both normal and water deficit conditions. Water stress markedly decreased the grain Se, iron (Fe), phosphorous (P), zinc (Zn) and magnesium (Mg) contents. Supplemental Se (Na2SeO4) improved the yield and quality of water stressed plants due to enhancement in the production of osmoprotectants and increased activity of antioxidant enzymes. The foliar spray of Se was more effective than Se fertigation and Se seed treatment. To the best of our knowledge, this is the first elaborate study that involved various Se application methods to evaluate the efficiency of Se supply to plants that would be crucial to develop better understanding of Se translocation and accumulation within crop plants under drought stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Water use by black wattle (Acacia mearnsii): implications for the link between removal of invading trees and catchment streamflow response

    CSIR Research Space (South Africa)

    Dye, P

    2004-01-01

    Full Text Available vegetation covers. Author’s review shows that very high rates of total evaporation are possible from dense infestations of black waffle occurring in riparian zones, where there are no soil water deficits through the year. Annual total evaporation from...

  9. Does Morphological and Anatomical Plasticity during the Vegetative Stage Make Wheat More Tolerant of Water Deficit Stress Than Rice?1[OPEN

    Science.gov (United States)

    Kadam, Niteen N.; Yin, Xinyou; Bindraban, Prem S.; Struik, Paul C.; Jagadish, Krishna S.V.

    2015-01-01

    Water scarcity and the increasing severity of water deficit stress are major challenges to sustaining irrigated rice (Oryza sativa) production. Despite the technologies developed to reduce the water requirement, rice growth is seriously constrained under water deficit stress compared with other dryland cereals such as wheat (Triticum aestivum). We exposed rice cultivars with contrasting responses to water deficit stress and wheat cultivars well adapted to water-limited conditions to the same moisture stress during vegetative growth to unravel the whole-plant (shoot and root morphology) and organ/tissue (root anatomy) responses. Wheat cultivars followed a water-conserving strategy by reducing specific leaf area and developing thicker roots and moderate tillering. In contrast, rice ‘IR64’ and ‘Apo’ adopted a rapid water acquisition strategy through thinner roots under water deficit stress. Root diameter, stele and xylem diameter, and xylem number were more responsive and varied with different positions along the nodal root under water deficit stress in wheat, whereas they were relatively conserved in rice cultivars. Increased metaxylem diameter and lower metaxylem number near the root tips and exactly the opposite phenomena at the root-shoot junction facilitated the efficient use of available soil moisture in wheat. Tolerant rice ‘Nagina 22’ had an advantage in root morphological and anatomical attributes over cultivars IR64 and Apo but lacked plasticity, unlike wheat cultivars exposed to water deficit stress. The key traits determining the adaptation of wheat to dryland conditions have been summarized and discussed. PMID:25614066

  10. Assessing water resource system vulnerability to unprecedented hydrological drought using copulas to characterize drought duration and deficit

    Science.gov (United States)

    Pflug, Georg; Hall, Jim W.; Hochrainer‐Stigler, Stefan

    2015-01-01

    Abstract Global climate models suggest an increase in evapotranspiration, changing storm tracks, and moisture delivery in many parts of the world, which are likely to cause more prolonged and severe drought, yet the weakness of climate models in modeling persistence of hydroclimatic variables and the uncertainties associated with regional climate projections mean that impact assessments based on climate model output may underestimate the risk of multiyear droughts. In this paper, we propose a vulnerability‐based approach to test water resource system response to drought. We generate a large number of synthetic streamflow series with different drought durations and deficits and use them as input to a water resource system model. Marginal distributions of the streamflow for each month are generated by bootstrapping the historical data, while the joint probability distributions of consecutive months are constructed using a copula‐based method. Droughts with longer durations and larger deficits than the observed record are generated by perturbing the copula parameter and by adopting an importance sampling strategy for low flows. In this way, potential climate‐induced changes in monthly hydrological persistence are factored into the vulnerability analysis. The method is applied to the London water system (England) to investigate under which drought conditions severe water use restrictions would need to be imposed. Results indicate that the water system is vulnerable to drought conditions outside the range of historical events. The vulnerability assessment results were coupled with climate model information to compare alternative water management options with respect to their vulnerability to increasingly long and severe drought. PMID:27609995

  11. Effect of Foliar Application of Phosphorus and Water Deficit on Yield and Yield Components of Winter Wheat (Cultivar Alvand

    Directory of Open Access Journals (Sweden)

    M. Vafapour

    2011-04-01

    Full Text Available In order to study the effects of foliar application of phosphorus (P and water deficit on yield and yield components of winter wheat (Triticum aestivum L., cv. Alvand, a split-plot experiment, with completely randomized blocks design and three replications, was carried out at the Research Farm of Boyer Ahmad Agricultural and Natural Resources Research Station, 13 km west of Yasouj, in 2008-2009. The main plots were irrigation at three levels (1- full irrigation (control, 2- deficit irrigation from the stem elongation to booting stage, and 3- deficit irrigation from booting stage to the end of growth period and the subplots were five levels of foliar application of P fertilizer (0, 3, 6, 9 and 12 kg/ha KH2PO4. The results showed that the effects of different irrigation regimes and foliar application of P were significant on all traits, and their interaction was significant on plant height, number of grain per spike, grain yield and biological yield. Full irrigation and foliar application of 6 kg/ha P produced the highest grain and biological yield (6000 and 14170 kg/ha, respectively and deficit irrigation from the stem elongation to booting stage without foliar application of P produced the lowest grain and biological yield (2920 and 8219 kg/ha, respectively. Foliar application of P affects significantly the evaluated traits only in drought-stress treatments and its effect was not significant in full irrigation treatment. In general, foliar application of 9 kg/ha P compensated the losses in wheat due to drought stress.

  12. Climate, intrinsic water-use efficiency and tree growth over the past 150 years in humid subtropical China

    Science.gov (United States)

    Li, Dawen; Fang, Keyan; Li, Yingjun; Chen, Deliang; Liu, Xiaohong; Dong, Zhipeng; Zhou, Feifei; Guo, Guoyang; Shi, Feng; Xu, Chenxi; Li, Yanping

    2017-01-01

    Influence of long-term changes in climate and CO2 concentration on intrinsic water-use efficiency (iWUE), defined as the ratio between net photosynthesis (A) and leaf conductance (g), and tree growth remain not fully revealed in humid subtropical China, which is distinct from other arid subtropical areas with dense coverage of broadleaf forests. This study presented the first tree-ring stable carbon isotope (δ13C) and iWUE series of Pinus massoniana from 1865 to 2013 in Fujian province, humid subtropical China, and the first tree-ring width standard chronology during the period of 1836–2013 for the Niumulin Nature Reserve (NML). Tree-ring width growth was limited by precipitation in July-August (r = 0.40, p climate. PMID:28182751

  13. Deficit irrigation and sustainable water-resource strategies in agriculture for China's food security

    National Research Council Canada - National Science Library

    Du, Taisheng; Kang, Shaozhong; Zhang, Jianhua; Davies, William J

    2015-01-01

    .... For future global food security, water use in agriculture must become sustainable. Agricultural water-use efficiency and water productivity can be improved at different points from the stomatal to the regional scale...

  14. Mitigation of Water Stress on Apple Trees under Rotational Irrigation Conditions by Increasing the Application Rate of Organic Fertilizers to Sandy Soils

    Science.gov (United States)

    Hamed, Lamy Mamdoh Mohamed; Ramadan Eid, Abdelraouf; Mohsmed Rabie Abdellatif Abdelaziz, Adel; Fathy Abdelsalam Essa, El-Sayed

    2016-04-01

    Egypt, as part of Mediterranean regions, is characterized by irregular and low rainfall amount which varies between (30-150 mm.year-1), and characterized also by high temperature which increase the rate of evapotranspiration from the cultivated soil. On the other hand, New reclaimed soils are mostly occupies around 84 % of total area of Egypt, which is mainly sandy soils. These soils generally characterized by low water capacity holding, soil organic matter, and weak in nutrients retention. Under these conditions which have a great influence on crop production, there is a great needing to increase the crop water use efficiency and increasing of nutrient retention in sandy soils. In this context, two field experiments were carried out on sand soil located in north Cairo-Egypt at the experimental farm of National Research Center, El-NUBARIA, (latitude 30° 30' N, and longitude 30° 19' E). The effect of compost rates on soil hydraulic characteristics, fruit yields, quality traits, and water use efficiency and productivity of apple tree (Apple Anna Cultivar), was studied under deficit irrigation conditions. Four rates of compost [I1: control, I2: 12 ton.ha-1., I3: 24 ton.ha-1., I4: 36 ton.ha-1. and I5:48 ton.ha-1.] were applied under irrigation frequencies of (IF1 :once per week; IF2 :twice per week, IF3 :three times per week). The obtained results indicated that by increasing the application rate of compost, the available water capacity and saturated water content of sandy soil have been enhanced. In the same time, the fruit yield, quality traits and water productivity were increased by increasing the application rate of compost. It is worthy to mention that the I5IF3 treatment gave the highest values of fruit yield, quality traits and water productivity, whereas I1IF1 treatment gave the lowest values of all the above mentioned variables. As result, for apple cultivation in El-NUBARIA region, the recommended rate of compost is 48 ton.ha-1 and irrigation frequency

  15. Electrical signals in avocado trees: responses to light and water availability conditions.

    Science.gov (United States)

    Oyarce, Patricio; Gurovich, Luis

    2010-01-01

    Plant responses to environmental changes are associated with electrical excitability and signaling; automatic and continuous measurements of electrical potential differences (DeltaEP) between plant tissues can be effectively used to study information transport mechanisms and physiological responses that result from external stimuli on plants. The generation and conduction of electrochemical impulses within plant different tissues and organs, resulting from abiotic and biotic changes in environmental conditions is reported. In this work, electrical potential differences are monitored continuously using Ag/AgCl microelectrodes, inserted 5 mm deep into sapwood at two positions in the trunks of several Avocado trees. Electrodes are referenced to a non polarisable Ag/AgCl microelectrode installed 20 cm deep in the soil. Systematic patterns of DeltaEP during absolute darkness, day-night cycles and different conditions of soil water availability are discussed as alternative tools to assess early plant stress conditions.

  16. Arabidopsis plants acclimate to water deficit at low cost through changes of carbon usage: an integrated perspective using growth, metabolite, enzyme, and gene expression analysis.

    Science.gov (United States)

    Hummel, Irène; Pantin, Florent; Sulpice, Ronan; Piques, Maria; Rolland, Gaëlle; Dauzat, Myriam; Christophe, Angélique; Pervent, Marjorie; Bouteillé, Marie; Stitt, Mark; Gibon, Yves; Muller, Bertrand

    2010-09-01

    Growth and carbon (C) fluxes are severely altered in plants exposed to soil water deficit. Correspondingly, it has been suggested that plants under water deficit suffer from C shortage. In this study, we test this hypothesis in Arabidopsis (Arabidopsis thaliana) by providing an overview of the responses of growth, C balance, metabolites, enzymes of the central metabolism, and a set of sugar-responsive genes to a sustained soil water deficit. The results show that under drought, rosette relative expansion rate is decreased more than photosynthesis, leading to a more positive C balance, while root growth is promoted. Several soluble metabolites accumulate in response to soil water deficit, with K(+) and organic acids as the main contributors to osmotic adjustment. Osmotic adjustment costs only a small percentage of the daily photosynthetic C fixation. All C metabolites measured (not only starch and sugars but also organic acids and amino acids) show a diurnal turnover that often increased under water deficit, suggesting that these metabolites are readily available for being metabolized in situ or exported to roots. On the basis of 30 enzyme activities, no in-depth reprogramming of C metabolism was observed. Water deficit induces a shift of the expression level of a set of sugar-responsive genes that is indicative of increased, rather than decreased, C availability. These results converge to show that the differential impact of soil water deficit on photosynthesis and rosette expansion results in an increased availability of C for the roots, an increased turnover of C metabolites, and a low-cost C-based osmotic adjustment, and these responses are performed without major reformatting of the primary metabolism machinery.

  17. Malbec grape (Vitis vinifera L.) responses to the environment: Berry phenolics as influenced by solar UV-B, water deficit and sprayed abscisic acid.

    Science.gov (United States)

    Alonso, Rodrigo; Berli, Federico J; Fontana, Ariel; Piccoli, Patricia; Bottini, Rubén

    2016-12-01

    High-altitude vineyards receive elevated solar ultraviolet-B (UV-B) levels so producing high quality berries for winemaking because of induction in the synthesis of phenolic compounds. Water deficit (D) after veraison, is a commonly used tool to regulate berry polyphenols concentration in red wine cultivars. Abscisic acid (ABA) plays a crucial role in the acclimation to environmental factors/signals (including UV-B and D). The aim of the present study was to evaluate independent and interactive effects of high-altitude solar UV-B, moderate water deficit and ABA applications on Vitis vinifera cv. Malbec berries. The experiment was conducted during two growing seasons with two treatments of UV-B (+UV-B and -UV-B), watering (+D and -D) and ABA (+ABA and -ABA), in a factorial design. Berry fresh weight, sugar content, fruit yield, phenolic compounds profile and antioxidant capacity (ORAC) were analyzed at harvest. Previous incidence of high UV-B prevented deleterious effects of water deficit, i.e. berry weight reduction and diminution of sugar accumulation. High UV-B increased total phenols (mainly astilbin, quercetin and kaempferol) and ORAC, irrespectively of the combination with other factors. Fruit yield was reduced by combining water deficit and high UV-B or water deficit and ABA. Two applications of ABA were enough to induced biochemical changes increasing total anthocyanins, especially those with higher antioxidant capacity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Photosynthetic characteristics of pineapple: Effects of CO{sub 2} enrichment, temperature variation and soil water deficit

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.; Goldstein, G.H.; Bartholomew, D.P. [Univ. of Hawaii, Honolulu, HI (United States)

    1995-06-01

    A six-month study of leaf gas exchange (GE; CO{sub 2} fixation, transpiration, conductance) and biomass of pineapple (Ananas Comosus (L.) Merr.), a plant with Crassulacean Acid Metabolism, was made using plants grown at 350 and 700 {mu}L L{sup -1} CO{sub 2} and day/night temperatures of 35/25, 30/25 and 30/20{degrees}C. After six months, a soil water deficit was imposed for two months. GE was monitored diurnally and leaf titratable acidity (TA), chlorophyll content, carbon isotope composition, chlorophyll fluorescence, and plant biomass were measured bimonthly. GE, TA, relative water content, and leaf osmotic and water potentials were measured every ten days during water stress. Daily carbon assimilation, water use efficiency, plant relative growth rate and net assimilation rate were significantly higher at 700 than at 350 {mu}L L{sup -1} CO{sub 2}. Total GE was greater during the day at 700 than at 350 {mu}L L{sup -1} CO{sub 2}. CO{sub 2} dark fixation was greater for plants in environments with a 10 {degrees}C diurnal temperature change (35/25 and 30/20{degrees}C). After imposing water stress, GE and TA declined substantially, and daytime GE decreased more than nocturnal values.

  19. Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees.

    Science.gov (United States)

    Sandra J. Bucci; Guillermo Goldstein; Frederick C. Meinzer; Augusto C. Franco; Paula Campanello; Fabián G. Scholz

    2005-01-01

    Seasonal regulation of leaf water potential (ΨL) was studied in eight dominant woody savanna species growing in Brazilian savanna (Cerrado) sites that experience a 5-month dry season. Despite marked seasonal variation in precipitation and air saturation deficit (D), seasonal differences in midday minimum Ψ...

  20. Crocin improves spatial learning and memory deficits in the Morris water maze via attenuating cortical oxidative damage in diabetic rats.

    Science.gov (United States)

    Ahmadi, M; Rajaei, Z; Hadjzadeh, M A; Nemati, H; Hosseini, M

    2017-03-06

    The purpose of the current study was to examine the influence of crocin on improving spatial memory deficits and cerebral oxidative damage in streptozotocin-induced diabetic rats. Crocin was administered intraperitoneally daily at doses of 15, 30 and 60mg/kg for 6 weeks. Spatial memory performance was measured in rats by the Morris water maze paradigm. Lipid peroxidation and total thiol levels as parameters of oxidative stress were assessed in the cerebral cortex at the end of week 6. Diabetic rats showed spatial learning and memory deficits in the Morris water maze which was accompanied by increased lipid peroxidation levels in the cerebral cortex. By contrast, chronic treatment with crocin (15, 30 and 60mg/kg, ip, 6 weeks) improved cognitive performance and lowered hyperglycaemia and oxidative stress in diabetic rats. In conclusion, the results suggest that beneficial effects of crocin on streptozotocin-induced memory dysfunction may be attributed to its antidiabetic and antioxidant activity, which could find clinical use in treating cognitive dysfunction in diabetics. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Delaying chloroplast turnover increases water-deficit stress tolerance through the enhancement of nitrogen assimilation in rice.

    Science.gov (United States)

    Sade, Nir; Umnajkitikorn, Kamolchanok; Rubio Wilhelmi, Maria Del Mar; Wright, Matthew; Wang, Songhu; Blumwald, Eduardo

    2017-07-27

    Abiotic stress-induced senescence in crops is a process particularly affecting the photosynthetic apparatus, decreasing photosynthetic activity and inducing chloroplast degradation. A pathway for stress-induced chloroplast degradation that involves the CHLOROPLAST VESICULATION (CV) gene was characterized in rice (Oryza sativa) plants. OsCV expression was up-regulated with the age of the plants and when plants were exposed to water-deficit conditions. The down-regulation of OsCV expression contributed to the maintenance of the chloroplast integrity under stress. OsCV-silenced plants displayed enhanced source fitness (i.e. carbon and nitrogen assimilation) and photorespiration, leading to water-deficit stress tolerance. Co-immunoprecipitation, intracellular co-localization, and bimolecular fluorescence demonstrated the in vivo interaction between OsCV and chloroplastic glutamine synthetase (OsGS2), affecting source-sink relationships of the plants under stress. Our results would indicate that the OsCV-mediated chloroplast degradation pathway is involved in the regulation of nitrogen assimilation during stress-induced plant senescence. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Effect of Deficit Irrigation Treatments on Vegetative Characteristics and Quantity and Quality of Golden Delicious Apple

    OpenAIRE

    I. Arji; B. Hassani; H. Ghamarnia

    2016-01-01

    Introduction: Since Iran is located in arid and semi-arid region of the world, so consumption and saving of water must be taking into account. Water is often a valuable natural resource, thus proper application methods - for increase water efficiency can be very important. Regulated deficit irrigation (RDI) is one of the most important methods to increase water use efficiency and fruit quality. Apple is one of the most important fruit trees from economical point of view. Studies showed that r...

  3. Estimating annual rainfall threshold for establishment of tree species in water-limited ecosystems using tree-ring data

    NARCIS (Netherlands)

    Lopez, B.C.; Holmgren, M.; Sabate, S.; Gracia, C.A.

    2008-01-01

    In arid and semi-arid ecosystems, water availability is discontinuous, highly variable, and characterized by discrete pulse events separated by long periods of limited resource availability. Plant recruitment in these ecosystems is also episodic and dependent on the water available during and after

  4. Rapid Water Uptake and Limited Storage Capacity at Height of Growing Season in Four Temperate Tree Species in a Central Pennsylvania Catchment

    Science.gov (United States)

    Gaines, K.; Meinzer, F. C.; Duffy, C.; Thomas, E.; Eissenstat, D. M.

    2014-12-01

    Water uptake and retention by trees affects their ability to cope with drought, as well as influences ground water recharge and stream flow. Historically, water has not often been limiting in Eastern U.S. forests. As a result, very little work has been done to understand the basics of timing of water use by vegetation in these systems. As droughts are projected to increase in length and severity in future decades, this focus is increasingly important, particularly for informing hydrologic models. We used deuterium tracer and sap flux techniques to study tree water transport on a forested ridge top with shallow soil in central Pennsylvania. Three trees of each of the species, Acer saccharum, Carya tomentosa, Quercus prinus, and Quercus rubrum were accessed by tree climbing and scaffolding towers. We hypothesized that contrasting vessel size of the tree species would affect the efficiency of water transport (tracer velocity) and contrasting tree size would affect tracer storage as estimated by tracer residence times. Trees were injected with deuterated water in July 2012. Leaves were sampled 15 times over 35 days, initially daily for the first week, then at regular intervals afterwards. The tracer arrived in the canopy of the study trees between 1 and 7 days after injection, traveling at a velocity of 2 to 19 m d-1. The tracer residence time was between 7 and 33 days. Although there was variation in tracer velocity and residence time in individual trees, there were no significant differences among wood types or species (P>0.05). The general patterns in timing of water use were similar to other studies on angiosperm trees in tropical and arid ecosystems. There was no evidence of longer residence times in the larger trees. Sap flux-based estimates of sap velocity were much lower than tracer estimates, which was consistent with other studies. Levels of sap flux and midday water potential measurements suggested that the trees were water-stressed. We observed relatively

  5. Effects of Salicylic Acid on Some Morphophysiological Characteristics of Border Flowers from Asteraceae Family under Water Deficit

    Directory of Open Access Journals (Sweden)

    majid zargarian

    2017-02-01

    Full Text Available Introduction: In order to improve physical and mental human healthy, development of the urban area landscape is necessary. Water deficit is one of the most important problems in arid and semi- arid regions. Water deficit causes to reduce growth of different plants parts, including roots, aerial parts, leaf area, height, dry weight, proteins, amino acids and chlorophyll. Using drought tolerance plantsisone solution. Moreover, one physiological method to decrease the hazardous effects of environmental stresses on plants is to applyplant growth regulators such as salicylic acid (SA. SA is one of the plant phenolic compounds in low amounts (mg/g wet weight or lower. This hormone can perform an important role in resistance to stresses. Asteraceae is one of the biggest plant families with over 20,000 species which is distributed worldwide in moderate and tropical regions. A lot of border flowers of this family are widely used in landscaping. Toselect drought tolerance flowers and application of materials that reducing stress effects, this experiment was conducted to investigate the effects of salicylic acid on some morphological and physiological characteristics of five border flowers of this family. Materials and Methods: The field experiment was conducted as split plot on randomized complete blocks design with four replications in which factors included two levels of water deficit (50, 100% FC as main plot and two levels of SA (0, 1mmol/L-1 as sub plot in the horticulturedepartment of faculty of Agriculture atFerdowsi University of Mashhad. In this investigation five border flowers (Ageratum houstonianum‘Blue Danube’, Tagetserecta ‘Discovery Yellow’, Tagetspatula‘Hero Harmony’, Zinnia elegans ‘Lilliput rose’andCallistephuschinensis ‘Milady Mix’ of Asteraceae family were chosen for study. The soil mixture was analyzed before starting the test. According to the result of physicochemical analysis of the soil, it had loamy texture

  6. Assessing water stress of desert Tamarugo trees using in situ data and very high spatial resolution remote sensing

    NARCIS (Netherlands)

    Chávez Oyanadel, R.O.; Clevers, J.G.P.W.; Herold, M.; Acevedo, E.; Ortiz, M.

    2013-01-01

    The hyper-arid Atacama Desert is one of the most extreme environments for life and only few species have evolved to survive its aridness. One such species is the tree Prosopis tamarugo Phil. Because Tamarugo completely depends on groundwater, it is being threatened by the high water demand from the

  7. Leaf water relations and sapflow in eastern cottonwood (Populus deltoides Bartr.) trees planted for phytoremediation of a groundwater pollutant

    Science.gov (United States)

    James M. Vose; Wayne T. Swank; Gregory J. Harvey; Barton D. Clinton; Christine Sobek

    2000-01-01

    Plants that remediate groundwater pollutants may offer a feasible alternative to the traditional and more expensive practices. Because its success depends on water use, this approach requires a complete understanding of species-specific transpiration patterns. The objectives of this study were (1) to quantify tree and stand-level transpiration in two age classes (whips...

  8. Water-deficit impact on fatty acid and essential oil composition and antioxidant activities of cumin (Cuminum cyminum L.) aerial parts.

    Science.gov (United States)

    Bettaieb, Iness; Knioua, Sana; Hamrouni, Ibtissem; Limam, Ferid; Marzouk, Brahim

    2011-01-12

    This study is designed to examine the effect of water deficit on growth, fatty acid and essential oil composition, and antioxidant activities of Cuminum cyminum aerial part extracts. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD). Plant growth (height, fresh and dry matter weights) as well as yield components were significantly increased under moderate water deficit and conversely reduced at severe level. Total fatty acid content decreased significantly with severity of constraint. Drought reduced considerably the proportions of major fatty acids and the unsaturated to saturated fatty acid ratio. The essential oil yield was 0.14% (based on the dry weight); it increased by 2.21-fold at MWD but decreased by 42.8% under SWD in comparison to the control. Drought results in the modification of the essential oil chemotype from 1-phenyl-1-butanol to 1-phenyl-1,2-ethanediol. Antioxidant activities of the acetone extracts were determined by two complementary test systems, namely, DPPH and β-carotene/linoleic acid. The highest activity was exhibited by moderately stressed plants and was reduced significantly under SWD. In control plants, the total phenolic amount was 10.23 mg GAE/g DW, which increased by 1.5-fold under MWD and decreased by 42% under SWD.

  9. Morphological Characteristics and Water-Use Efficiency of Siberian Elm Trees (Ulmus pumila L. within Arid Regions of Northeast Asia

    Directory of Open Access Journals (Sweden)

    Go Eun Park

    2016-11-01

    Full Text Available The Siberian elm (Ulmus pumila L. is one of the most commonly found tree species in arid areas of northeast Asia. To understand the morphological and physiological characteristics of Siberian elms in arid regions, we analyzed leaves from seven study sites (five arid or semi-arid and two mesic in China, Mongolia and the Republic of Korea, which covered a wide range of average annual precipitation (232 mm·year−1 to 1304 mm·year−1 under various aridity indexes (AI and four different microenvironments: sand dune, steppe, riverside and forest. The traits of Siberian elms varied widely along different annual precipitation (P and AI gradients. Tree height (H, leaf size (LS and stomatal area per unit leaf area (AS/AL decreased with increasing AI, whereas leaf mass per unit leaf area (LMA and water-use efficiency (WUE increased significantly. In addition, trees at the five arid sites showed significant differences in LS, LMA and AS/AL but not in H and WUE. Thus, our study indicated that indigenous Siberian elm trees in arid areas have substantially altered their morphological and physiological characteristics to avoid heat stress and increase water conservation in comparison to mesic areas. However, their changes differed depending on the surrounding microenvironment even in arid areas. Trees in sand dunes had a smaller LS, higher LMA, thicker leaf cuticle layer and higher stomatal density and AS than those in steppes and near a riverside.

  10. Water-use efficiency within a selection of indigenous and exotic tree species in South Africa as determined using sap flow and biomass measurements

    CSIR Research Space (South Africa)

    Gush, Mark B

    2008-10-01

    Full Text Available the grasslands or scrublands they typically replace, and hence reduce water yield (streamflow) from afforested catchments. Conversely, there is a widespread perception that indigenous tree species, in contrast to exotic plantation species, are water...

  11. Yield Response of Spring Maize to Inter-Row Subsoiling and Soil Water Deficit in Northern China.

    Science.gov (United States)

    Liu, Zhandong; Qin, Anzhen; Zhao, Ben; Ata-Ul-Karim, Syed Tahir; Xiao, Junfu; Sun, Jingsheng; Ning, Dongfeng; Liu, Zugui; Nan, Jiqin; Duan, Aiwang

    2016-01-01

    Long-term tillage has been shown to induce water stress episode during crop growth period due to low water retention capacity. It is unclear whether integrated water conservation tillage systems, such asspringdeepinter-row subsoiling with annual or biennial repetitions, can be developed to alleviate this issue while improve crop productivity. Experimentswere carried out in a spring maize cropping system on Calcaric-fluvicCambisolsatJiaozuoexperimentstation, northern China, in 2009 to 2014. Effects of threesubsoiling depths (i.e., 30 cm, 40 cm, and 50 cm) in combination with annual and biennial repetitionswasdetermined in two single-years (i.e., 2012 and 2014)againstthe conventional tillage. The objectives were to investigateyield response to subsoiling depths and soil water deficit(SWD), and to identify the most effective subsoiling treatment using a systematic assessment. Annualsubsoiling to 50 cm (AS-50) increased soil water storage (SWS, mm) by an average of8% in 0-20 cm soil depth, 19% in 20-80 cm depth, and 10% in 80-120 cm depth, followed by AS-40 and BS-50, whereas AS-30 and BS-30 showed much less effects in increasing SWS across the 0-120 cm soil profile, compared to the CK. AS-50 significantly reduced soil water deficit (SWD, mm) by an average of123% during sowing to jointing, 318% during jointing to filling, and 221% during filling to maturity, compared to the CK, followed by AS-40 and BS-50. An integrated effect on increasing SWS and reducing SWD helped AS-50 boost grain yield by an average of 31% and biomass yield by 30%, compared to the CK. A power function for subsoiling depth and a negative linear function for SWD were used to fit the measured yields, showing the deepest subsoiling depth (50 cm) with the lowest SWD contributed to the highest yield. Systematic assessment showed that AS-50 received the highest evaluation index (0.69 out of 1.0) among all treatments. Deepinter-row subsoilingwith annual repetition significantly boosts yield by

  12. Yield and water use efficiency of deficit-irrigated maize in a semi ...

    African Journals Online (AJOL)

    Scarcity of water is the most severe constraint for development of agriculture in arid and semi-arid areas. Under these conditions, the need to use the available water economically and efficiently is unquestionable. Based on the actual crop need, the irrigation management has to be improved so that the water supply to the ...

  13. Effects of Foliar Applications of Sulfur, Nitrogen and Phosphorus on Castor Bean (Ricinus cmmunis L. Seed Yield and its Components under Water Deficit Conditions

    Directory of Open Access Journals (Sweden)

    M. Mosavi

    2015-08-01

    Full Text Available To determine the effects of foliar applications of some macroelements on castor seed yield and its components under drought stress conditions, an experiment was conducted at the Agricultural Research Center of East Azerbaijan province. A factorial experiment, based on randomized complete block design with three replications, was carried out during 2013 growing season. Treatment factors consisted of irrigations with two levels (no water deficit and water deficit during grain filling stage and of foliar applications of macroelements with four levels [control, wettable sulfur (0.2 percent, nitrogen (urea: 0.6 percent and phosphor (super phosphate triple: 0.4 percent. Traits studied were: plant height, number of inflorescence, number of lateral branches, number of leaves, leaf temperature, relative water content, number of seeds per plant, 1000-kernal weight and seed yield. All traits, except number of inflorescence, were affected significantly by drought stress. Water deficit reduced plant height, number of leaves, number of seeds per plant, 1000-kernal weight, seed yield, relative water content, while it increased leaf temperature. Number of lateral branches was affected significantly by interaction between factors. Maximum latral branches (1.86 were obtained under non-stress treatment with nitrogen foliar application. Moderate drought stress had significant effect on leaf temperature and relative water content. It seems that, these traits can be used in determination of water deficit effects on castor bean.

  14. Responses of plant water use to a severe summer drought for two subtropical tree species in the central southern China

    Directory of Open Access Journals (Sweden)

    Zidong Luo

    2016-12-01

    New hydrological insights: The results show that a decrease in water use during the drought for both two species is closely associated with an increase in vapor pressure deficit and a decrease in stem water potential. The two species appear to be anisohydric, but to a different degree in response to the drought. The hydrodynamic water potential gradient (Δψ maintains relatively constant with an average value of 0.59 MPa for C. camphora, and 1.59 MPa for O. fragrans. O. fragrans is less sensitive to drought than C. camphora, while C. camphora shows an effective survival mechanism via leaf shedding and dieback of shoots.

  15. Beneficial Effects of Mycorrhizal Fungi on Growth Characteristics and Nutrients Uptake by Plane Tree (Platanus orientalis L, Subjected to Deficit Irrigation

    Directory of Open Access Journals (Sweden)

    H. Alipour Amraie1

    2016-12-01

    Full Text Available Plane tree is one of the important trees cultivated in urban landscapes of Iran and often suffers from different nutritional issues including deficiency and toxicity of mineral nutrients. Mycorrhizal fungi have been introduced to increase growth and quality of plants in horticulture. To study the combined effect of two mycorrhizal fungi (G. mosseae and G. intraradices on plane trees, an experiment was conducted based on a randomized complete block design with 4 treatments and 6 replicates. Treatments included control (without fertilizer, livestock manure, complete fertilizer (20:5:10 and manure + fertilizer + mycorrhizal fungi. Some traits and indices including phosphorus, nitrogen, iron and zinc contents, leaf fresh weight, current year growth and total soluble carbohydrate and chlorophyll contents were evaluated. The results showed the positive effects of manure, fertilizer and mycorrhizal fungi on the plane tree, as these treatments significantly increased all examined parameters except for current year growth. Contents of phosphorus, nitrogen, zinc, iron, chlorophyll and total soluble sugar increased by 400%, 20%, 500%, 34%, 41% and 23%, in mycorrhizal-treated plants, respectively, as compared to the control trees. The results of this study showed a promising effect of the mycorrhizal fungi to be applied along with fertilizer and manure as an appropriate biological fertilizer for plane tree.

  16. Tree water potentials supporting an explanation for the occurrence of Vachellia erioloba in the Namib Desert (Namibia

    Directory of Open Access Journals (Sweden)

    Joachim H. A. Krug

    2017-09-01

    Full Text Available Background Site-vegetation relations of Vachellia erioloba, Faidherbia albida, Euclea pseudebenus and Tamarix usneoides in two contrasting locations in the Namib Desert (Namibia were evaluated with the goal to relate soil water availability to the occurrence of trees under hyper-arid conditions. Methods Plant water potentials were measured using a pressure chamber in the field. Pre-dawn water potentials were assessed to reflect the soil water potential of the rhizosphere. Midday water potentials were measured to assess the strongest negative water potential applied by the sample trees. Results Pre-dawn water potentials and midday water potentials indicated access to soil water in the rhizosphere and by this, provide an explanation for an occurrence of V. erioloba within the extreme environmental conditions of sand dunes in the Namib Desert. Diurnal ranges seem to reflect more and less suitable stands, in terms of soil water availability, within the sampling sites. While the impact of the ephemeral Kuiseb river on soil water availability was assessed through the four species’ plant-internal water relations, comparable pre-dawn water potentials of V. erioloba at both sites indicate soil water availability also in the dunes of Namibrand. The extreme midday water potentials of the dune plants possibly show the upper limit of tolerance for V. erioloba. Conclusions The preliminary data provide an explanation of the occurrence and distribution of the investigated species in beds of ephemeral rivers and on dunes under the hyper-arid climatic conditions of the Namib Desert and qualify suitability within the assessed sites. Understanding the plant-physiological processes and assessing the plant-internal water potential provides a valuable tool to evaluate soil water availability within the rhizosphere and to describe an adaptation potential of investigated species. The comparability of pre-dawn water potentials at both sites indicates unexpected soil

  17. Effects of tree species, water and nitrogen on mycorrhizal C flux

    Science.gov (United States)

    Menyailo, O.; Matvienko, A.

    2012-12-01

    Mycorrhiza plays an important role in global carbon cycle, especially, in forest soils, yet the effect of tree species on the amount and timing of C transfer through roots to myccorhiza is largely unknown. We studied the C transport to mycorrhiza under 6 most commonly dominant in boreal forests tree species using the mesh collars installed at the Siberian afforestation experiment. The CO2 flux from mycorrhizal and non-mycorrhizal mesh collars indicated the mycorrhizal C flux. Tree species strongly differed in C flux to mycorrhiza: more C was transferred by deciduous species than by conifers. The mycorrhizal CO2 flux was not linked to soil temperature but rather to trees phenology and to photosynthetic activity. All tree species transfered more carbon to mycorrhiza during the second half of summer and in September, this is because all the carbon photosynthesized earlier is used for building the tree biomass. Seasonal variation in C transfer to mycorrhiza was much larger than hourly variation (within a day). Nitrogen application (50 kg/ha) increased mycorrhizal C flux only under Scots pine, but not under larch, thus the effect of N application is tree species dependent. We found under most tree species that more C was transferred by trees to mycorrhiza in root-free collars, where the soil moisture was higher than in collars with roots. This suggests that trees preferentially support those parts of mycorrhiza, which can gain extra-resources.

  18. Effects of Foliar Rates of Methanol Applications on some of Traits Related to Seed Yield of Sunflower (Helianthus annuus L. under Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    E. Khalilvand Behrouzyar

    2014-07-01

    Full Text Available To investigate the effects of rates of methanol foliar applications under water deficit stress on someof traits related to seed yield of sunflower (Helianthus annuus L, a split plot experiment was conducted during growing seasons of 2011-2012. Treatments were four levels of water deficit stresses a1: severe stress (irrigation at 25% FC, a2: mild stress (irrigation at 50% FC, a3: fair stress (irrigation at 75% FC and a4: normal irrigation (irrigation at 100% FC and six levels of foliar methanol applications [b1:0, b2:7, b3:14, b4:21, b5:28 and b6:35 (v/v]. The analysis of variance showed significant effect of interaction between water deficit stress and methanol rates of foliar applications on seed yield per plant, dry weight per plant, number of seeds per head (p

  19. Temporal dynamics of stomatal conductance of plants under water deficit: can homeostasis be improved by more complex dynamics?

    Directory of Open Access Journals (Sweden)

    Gustavo Maia Souza

    2004-07-01

    Full Text Available In this study we hypothesized that chaotic or complex behavior of stomatal conductance could improve plant homeostasis after water deficit. Stomatal conductance of sunflower and sugar beet leaves was measured in plants grown either daily irrigation or under water deficit using an infrared gas analyzer. All measurements were performed under controlled environmental conditions. In order to measure a consistent time series, data were scored with time intervals of 20s during 6h. Lyapunov exponents, fractal dimensions, KS entropy and relative LZ complexity were calculated. Stomatal conductance in both irrigated and non-irrigated plants was chaotic-like. Plants under water deficit showed a trend to a more complex behaviour, mainly in sunflower that showed better homeostasis than in sugar beet. Some biological implications are discussed.Este estudo testou a hipótese de que a condutância estomática de uma população de estômatos em uma folha poderia apresentar um comportamento caótico ou complexo sob diferentes condições hídricas, o que poderia favorecer a capacidade homeostática das plantas. A condutância estomática em folhas de girassol e de beterraba cultivadas com irrigação diária e sob deficiência hídrica foi medida com um analisador de gás por infra-vermelho em condições controladas. Os dados foram registrados a cada 20s durante 6h. As séries temporais obtidas foram analisadas por meio dos coeficientes de Lyapunov, dimensão fractal, entropia KS e complexidade LZ relativa. A condutância estomática nas plantas cultivadas com e sem deficiência hídrica exibiu um comportamento provavelmente caótico. As plantas sob estresse hídrico mostraram uma tendência para um comportamento mais complexo, principalmente as plantas de girassol cuja capacidade homeostática foi superior. Algumas implicações biológicas destes comportamentos são discutidas no texto.

  20. WATER DEFICIT ENSURES THE PHOTOCHEMICAL EFFICIENCY OF Copaifera langsdorffii Desf1

    Directory of Open Access Journals (Sweden)

    Angélica Lino Rodrigues

    2017-02-01

    Full Text Available ABSTRACT The intensity and frequency of drought periods has increased according to climate change predictions. The fast overcome and recovery are important adaptive features for plant species found in regions presenting water shortage periods. Copaifera langsdorffii is a neotropical species that has developed leaves presenting physiological mechanisms and morphological adaptations that allow its survival under seasonal water stress. We aimed in this work to observe substantial physiological responses for water saving and damage representative to the photochemical reaction after exposed plants to water stress and to subsequent recovery. We found in plants mechanisms to control water loss through the lower stomatal conductance, even after rehydration. It goes against the rapid recovery of leaves, indicated by the relative water content values restored to previously unstressed plants. Stomatal conductance was the only variable presenting high plasticity index. In photochemical activity, the species presented higher photochemical quenching, electron transport rate and effective quantum yield of photosystem II when they were subjected to rehydration after water stress period. Our results suggest that C. langsdorffii presented rapid rehydration and higher photochemical efficiency even after water restriction. These data demonstrate that this species can be used as a model for physiological studies due to the adjustment developed in response to different environmental schemes.

  1. CASE STUDY: Jordan — Dealing with the water deficit in Jordan ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-12-20

    Dec 20, 2010 ... Recycling household water to irrigate home gardens makes good environmental and financial sense Water is a precious commodity in much of the Middle East and North Africa, too valuable to pour down the drain. So researchers in Jordan found a way to reuse household wastewater for use in urban ...

  2. Farm level optimal water management : assistant for irrigation under deficit (FLOW-AID)

    NARCIS (Netherlands)

    Balendonck, J.; Stanghellini, C.; Hemming, J.; Kempkes, F.L.K.; Tuijl, van B.A.J.

    2008-01-01

    FLOW-AID is an on-going 6th Framework European project (2006-2009) with the objective to contribute to sustainable irrigated agriculture by developing an irrigation management system that can be used for crop production in cases with limited water supply and marginal water quality. The project

  3. Deficit hídrico e secamento parcial do sistema radicular em pomar de lima ácida Water deficit and partial rootzone drying in an acid lime orchard

    Directory of Open Access Journals (Sweden)

    Antonio Hélder Rodrigues Sampaio

    2010-10-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito do deficit hídrico associado ao secamento parcial do sistema radicular ("partial rootzone drying", PRD na produção e eficiência de uso de água, em pomar de lima ácida 'Tahiti', na Região do Semiárido baiano. Utilizou-se o delineamento de blocos ao acaso, com seis tratamentos e seis repetições. Os tratamentos com PRD foram realizados pela alternância periódica (7, 14 ou 21 dias dos lados em que o microaspersor localizava-se em relação às plantas. Esses tratamentos foram conduzidos com lâmina d'água equivalente a 50% da evapotranspiração da cultura (ETc e comparados ao tratamento com deficit hídrico de 50% da ETc com microaspersor fixo em um dos lados das plantas, e ao tratamento 100% da ETc, com aspersores de ambos os lados das plantas. Avaliou-se também o PRD (21 dias com diminuição da irrigação em 25% da ETc. O PRD com 50% da ETc não difere do tratamento com esse mesmo deficit e sem alternância de lados da irrigação, em termos de produtividade, eficiência do uso da água, e diâmetro e peso dos frutos, independentemente do período de alternância dos lados de irrigação. O PRD com diminuição da irrigação em 25% da ETc não causa perdas em relação à condição sem deficit e sem localização da irrigação.The objective of this work was to evaluate the effect of water deficit and of partial rootzone drying (PRD on the yield and water use efficiency in a 'Tahiti' lime orchard, in the Semiarid Region of Bahia state, Brazil. The experiment was carried out in a randomized block design, with six treatments and six replicates. Treatments with PRD were carried out by the periodic alternance (7, 14 or 21 days of the sides in which the micro sprinklers were located in relation to the plants. These treatments were performed with a water depth equivalent to 50% of crop evapotranspiration (ETc. They were compared to the treatment with 50% water deficit, using one fixed

  4. Implications of high-temperature events and water deficits on protein profiles in wheat (Triticum aestivum L. cv. Vinjett) grain

    DEFF Research Database (Denmark)

    Yang, Fen; Jørgensen, Anders Dysted; Li, Huawei

    2011-01-01

    of interaction of water deficits and/or a high-temperature event (32 degrees C) during vegetative growth (terminal spikelet) with either of these stress events applied during generative growth (anthesis) in wheat. Influence of combinations of stress on protein fractions (albumins, globulins, gliadins......Increased climatic variability is resulting in an increase of both the frequency and the magnitude of extreme climate events. Therefore, cereals may be exposed to more than one stress event in the growing season, which may ultimately affect crop yield and quality. Here, effects are reported...... and glutenins) in grains and stress-induced changes on the albumin and gliadin proteomes were investigated by 2-DE and MS. The synthesis of individual protein fractions was shown to be affected by both the type and time of the applied stresses. Identified drought or high-temperature-responsive proteins included...

  5. Climate change uncertainty and risk assessment in Iran during twenty-first century: evapotranspiration and green water deficit analysis

    Science.gov (United States)

    Karandish, Fatemeh; Mousavi, Seyed-Saeed

    2018-01-01

    For a 120-year period, the projected effects of climate change on annual, seasonal, and monthly potential evapotranspiration (ETo) and green water deficit (GWD) were analyzed involving the associated uncertainties for five climatic zones of Iran. Analysis was carried out using data obtained from 15 general circulation models (GCMs) under three SRES scenarios of A1B, A2, and B1 which were downscaled using LARS-WG for 52 synoptic stations up to 2100. The majority of GCMs as well as the median of the ensemble for each scenario project a positive change in both ETo and GWD. A total of 5.8-19.8 % increase in annual ETo, drier than normal wet seasons, as well as 2.3-56.4 % increase in ETo during December-March period well represent a probable increase in the hydrological water requirement in Iran under global warming. Regarding GWD, the country will experience more arid years requiring 113.7 × 103-576.8 × 103 Mm3 more water to supply annual atmospheric water demand. Semi-arid and Mediterranean regions, principal agricultural producer areas of Iran, will be the most vulnerable part of the country due to 1-38.6 % increase in annual GWD under climate change. In addition, water scarcity for irrigated agriculture will enhance in all climatic zones due to 0.9-41 % increase GWD in June-August. However, rain-fed agriculture might be less affected in the hyper-humid and Mediterranean regions because of 1.1-105.3 % reduction in GWD during wet season. Nevertheless, uncertainty analysis revealed that given results for monthly timescale as well as those for times and regions with lower ETo will be the most uncertain. Based on the results, suitable adaptation solutions are highly required to be undertaken to relieve the extra pressure on the decreased blue water resources in the future.

  6. Climate change uncertainty and risk assessment in Iran during twenty-first century: evapotranspiration and green water deficit analysis

    Science.gov (United States)

    Karandish, Fatemeh; Mousavi, Seyed-Saeed

    2016-12-01

    For a 120-year period, the projected effects of climate change on annual, seasonal, and monthly potential evapotranspiration (ETo) and green water deficit (GWD) were analyzed involving the associated uncertainties for five climatic zones of Iran. Analysis was carried out using data obtained from 15 general circulation models (GCMs) under three SRES scenarios of A1B, A2, and B1 which were downscaled using LARS-WG for 52 synoptic stations up to 2100. The majority of GCMs as well as the median of the ensemble for each scenario project a positive change in both ETo and GWD. A total of 5.8-19.8 % increase in annual ETo, drier than normal wet seasons, as well as 2.3-56.4 % increase in ETo during December-March period well represent a probable increase in the hydrological water requirement in Iran under global warming. Regarding GWD, the country will experience more arid years requiring 113.7 × 103-576.8 × 103 Mm3 more water to supply annual atmospheric water demand. Semi-arid and Mediterranean regions, principal agricultural producer areas of Iran, will be the most vulnerable part of the country due to 1-38.6 % increase in annual GWD under climate change. In addition, water scarcity for irrigated agriculture will enhance in all climatic zones due to 0.9-41 % increase GWD in June-August. However, rain-fed agriculture might be less affected in the hyper-humid and Mediterranean regions because of 1.1-105.3 % reduction in GWD during wet season. Nevertheless, uncertainty analysis revealed that given results for monthly timescale as well as those for times and regions with lower ETo will be the most uncertain. Based on the results, suitable adaptation solutions are highly required to be undertaken to relieve the extra pressure on the decreased blue water resources in the future.

  7. Ecofisiologia de plantas jovens de mogno-africano submetidas a deficit hídrico e reidratação Ecophysiology of young African mahogany plants subjected to water deficit and rewetting

    Directory of Open Access Journals (Sweden)

    Marcos Paulo Ferreira de Albuquerque

    2013-01-01

    Full Text Available O objetivo deste trabalho foi avaliar a capacidade de plantas jovens de mogno-africano (Khaya ivorensis em recuperar seu status hídrico e trocas gasosas após período de deficit hídrico. Plantas com aproximadamente 315 dias, irrigadas (controle e não irrigadas, foram avaliadas aos 14 dias da suspensão da irrigação e após um, três e sete dias da retomada da irrigação (reidratação. No dia 14, o potencial hídrico foliar de antemanhã (Ψam das plantas estressadas foi reduzido a -2,66 MPa. Com a restrição hídrica, foram observadas reduções significativas no conteúdo relativo de água na antemanhã (redução de 32%, na taxa de assimilação líquida de CO2 (90%, na condutância estomática (95%, na transpiração (93% e na razão entre concentração intercelular e ambiental de CO2 (37%. Durante a reidratação, o status hídrico das plantas estressadas foi restabelecido após três dias. As trocas gasosas também se restabeleceram, mas de forma mais lenta que o status hídrico. Sob deficit hídrico, a concentração de prolina aumentou e a de carboidratos solúveis totais diminuiu. Plantas jovens de mogno-africano são tolerantes ao deficit hídrico moderado.The objective of this work was to evaluate the capacity of young plants of African mahogany (Khaya ivorensis to recover their water status and gas exchange after water deficit. Plants with approximately 315 days, irrigated (control and non-irrigated, were evaluated after water was withheld for 14 days, and after one, three, and seven days of irrigation resumption (rehydration. On day 14, the predawn leaf water potential (Ψam of stressed plants was reduced to -2.66 MPa. With water deficit, significant decreases were observed in predawn relative water content (32% reduction, in net assimilation rate of CO2 (90%, in stomatal conductance (95%, in transpiration (93%, and in intercellular to ambient ratio of CO2 concentration (37%. During rehydration, the water status of stressed

  8. A dual stable-isotope approach to analyse the linkages between tree water fluxes and soil water pools in a Mediterranean mountain catchment

    Science.gov (United States)

    Llorens, Pilar; Cayuela, Carles; Sánchez-Costa, Elisenda; Gallart, Francesc; Latron, Jérôme

    2017-04-01

    This work uses a dual isotope-based approach (18O, 2H) to examine the mixing of water in the soil and the linkages between tree water fluxes and soil water pools in a Mediterranean mountain catchment (Vallcebre Research Catchments, NE Spain, 42° 12'N, 1° 49'E). Since May 2015, water-isotopes have been monitored in rainfall, throughfall and stemflow below a Scots pine stand and in stream water at the Can Vila (0.56 km2) catchment outlet. Moreover, fortnightly (From May to December 2015) soil samples (10, 20, 30, 50 and 100 cm), xylem samples (3 Scots pines) and mobile soil water samples in low-suction lysimeters (20, 50 and 100 cm) and in a piezometer (150-300 cm deep) were collected at the same stand. Water from soil and xylem samples was extracted by cryogenic vacuum distillation and isotope analyses were obtained by infrared spectroscopy. All this information has been combined with continuous measurement of meteorological, soil moisture and water potential, piezometric levels and hydrological variables at the stand and catchment scales. Stable isotopes ratios of bound soil water fell below the local meteoric water line (LMWL), with more evaporative enrichment in the shallow horizons. On the contrary, mobile soil water (low suction lysimeters) and groundwater fell along the LMWL, well mixed with stream water. The differences observed between these two water pools remained similar during the whole study period. Stable isotopes ratios indicate that Scots pine trees use shallow bound soil water during the whole study period. No marked changes in depth of water uptake were observed, presumably due to the availability of water in the shallow horizons, even during the summer months.

  9. Dealing with water deficit in Atta ant colonies: large ants scout for water while small ants transport it

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Da-Silva

    2012-07-01

    Leafcutter ants (Atta sexdens rubropilosa (Forel 1908 have an elaborate social organization, complete with caste divisions. Activities carried out by specialist groups contribute to the overall success and survival of the colony when it is confronted with environmental challenges such as dehydration. Ants detect variations in humidity inside the nest and react by activating several types of behavior that enhance water uptake and decrease water loss, but it is not clear whether or not a single caste collects water regardless of the cost of bringing this resource back to the colony. Accordingly, we investigated water collection activities in three colonies of Atta sexdens rubropilosa experimentally exposed to water stress. Specifically, we analyzed whether or not the same ant caste foraged for water, regardless of the absolute energetic cost (distance of transporting this resource back to the colony. Our experimental design offered water sources at 0 m, 1 m and 10 m from the nest. We studied the body size of ants near the water sources from the initial offer of water (time  =  0 to 120 min, and tested for specialization. We observed a reduction in the average size and variance of ants that corroborated the specialization hypothesis. Although the temporal course of specialization changed with distance, the final outcome was similar among distances. Thus, we conclude that, for this species, a specialist (our use of the word “specialist” does not mean exclusive task force is responsible for collecting water, regardless of the cost of transporting water back to the colony.

  10. Flood regime and water table determines tree distribution in a forest-savanna gradient in the Brazilian Pantanal.

    Science.gov (United States)

    Ferreira-Júnior, Walnir G; Schaefer, Carlos E G R; Cunha, Cátia N; Duarte, Temilze G; Chieregatto, Luiz C; Carmo, Flávia M S

    2016-01-01

    This study aimed to recognized the preferential location of species of the tree sinusiae in response to a moisture gradient in Pantanal Matogrossense, Brazil. We established sampling plots of arboreal sinusiae along a soil moisture and flood gradient. Piezometers were installed, allowing monthly measurements of water table depth and flood height during one year. Detrended Correspondence Analysis, Gradient Direct Analysis, Multi-response Permutation Procedures and Indicator Species Analysis were performed to evaluate the effect of moisture gradient on tree distribution. The annual variation of water table is shallower and similar in Seasonally Flooded Forest and Termite Savanna, with increasing depths in Open Savanna, Savanna Forest and Dry Forest. Circa 64% of the species were characterized as having a preferential location in "terrestrial habitats normally not subjected to inundation", while 8% preferentially occur in "wet habitats". Lowest tree richness in flood-affected vegetation types is related to both present-day high climatic seasonality and Late Pleistocene dry paleoclimates in the Pantanal wetland. The tree distribution across different formations in the Pantanal shows a direct relationship with soil moisture gradient.

  11. Differential Responses of Water Uptake Pathways and Expression of Two Aquaporin Genes to Water-Deficit in Rice Seedlings of Two Genotypes

    Directory of Open Access Journals (Sweden)

    Xu Ai-hua

    2017-07-01

    Full Text Available Water-deficit (WD is a major abiotic stress constraining crop productivity worldwide. Zhenshan 97 is a drought-susceptible rice genotype, while IRAT109 is a drought-resistant one. However, the physiological basis of the difference remains unclear. These two genotypes had similar total water uptake rates under both WD and well-watered (WW conditions, and their water uptake rates under WD were significantly decreased compared with those under WW. However, the water uptake rate via the cell-to-cell pathway was significantly increased in Zhenshan 97 but decreased in IRAT109 under WD, whereas the opposite trends were observed through the apoplastic pathway. These results indicated that the stress responses and relative contributions of these two water uptake pathways were associated with rice genotype under WD. The expression levels of OsPIP2;4 and OsPIP2;5 genes were significantly higher in roots of Zhenshan 97 than in IRAT109 under the two conditions. OsPIP2;4 expression in roots was significantly up-regulated under WD, while OsPIP2;5 expression showed no significant change. These results suggest that the expression levels of OsPIP2;4 and OsPIP2;5 in rice are dependent on genotype and water availability. Compared with Zhenshan 97, IRAT109 had a higher root dry weight, water uptake rate and xylem sap flow rate, and lower leaf water potential and root porosity under WD, which might be responsible for the drought resistance in IRAT109.

  12. The beneficial effects of olibanum on memory deficit induced by hypothyroidism in adult rats tested in Morris water maze.

    Science.gov (United States)

    Hosseini, Mahmoud; Hadjzadeh, Mosa Al-Reza; Derakhshan, Mohammad; Havakhah, Shahrzad; Rassouli, Fatemeh Behnam; Rakhshandeh, Hassan; Saffarzadeh, Fatema

    2010-03-01

    Functional consequences of hypothyroidism include impaired learning and memory and inability to produce long-term potentiation (LTP) in hippocampus. Olibanum has been used for variety of therapeutic purposes. In traditional medicine, oilbanum is used to enhance learning and memory. In the present study the effect of olibanum on memory deficit in hypothyroid rats was investigated. Male wistar rats were divided into four groups and treated for 180 days. Group 1 received tap drinking water while in group 2, 0.03% methimazol was added to drinking water. Group 3 and 4 were treated with 0.03% methimazole as well as 100 and 500 mg/kg olibanum respectively. The animals were tested in Morris water maze. The swimming speed was significantly lower and the distance and time latency were higher in group 2 compared with group 1. In groups 3 and 4 the swimming speed was significantly higher while, the length of the swim path and time latency were significantly lower in comparison with group 2. It is concluded that methimazole-induced hypothyroidism impairs learning and memory in adult rats which could be prevented by using olibanum.

  13. Soil warming increased whole-tree water use of Pinus cembra at the treeline in the Central Tyrolean Alps.

    Science.gov (United States)

    Wieser, Gerhard; Grams, Thorsten E E; Matyssek, Rainer; Oberhuber, Walter; Gruber, Andreas

    2015-03-01

    This study quantified the effect of soil warming on sap flow density (Qs) of Pinus cembra L. at the treeline in the Central Tyrolean Alps. To enhance soil temperature we installed a transparent roof construction above the forest floor around six trees. Six other trees served as controls in the absence of any manipulation. Roofing enhanced growing season mean soil temperature by 1.6, 1.3 and 1.0 °C at 5, 10 and 20 cm soil depth, respectively, while soil water availability was not affected. Sap flow density (using Granier-type thermal dissipation probes) and environmental parameters were monitored throughout three growing seasons. During the first year of treatment, no warming effect was detected on Qs. However, soil warming caused Qs to increase significantly by 11 and 19% above levels in control trees during the second and third year, respectively. This effect appeared to result from warming-induced root production, a reduction in viscosity and perhaps an increase also in root hydraulic conductivity. Hardly affected were leaf-level net CO2 uptake rate and conductance for water vapour, so that water-use efficiency stayed unchanged as confirmed by needle δ(13)C analysis. We conclude that tree water loss will increase with soil warming, which may alter the water balance within the treeline ecotone of the Central Austrian Alps in a future warming environment. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. :Ffowering 'Trees-

    Indian Academy of Sciences (India)

    The tree is a host of lac insects which secrete a resinous substance that yields shellac or lac. A ruby-coloured gum known as Bengal Kino is collected from the incisions made in the bark. The wood, resistant to water, is used in water-well work. The seeds are used as anthelmintic and as an antidote for snake-bite.

  15. Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots1[OPEN

    Science.gov (United States)

    Durand, Mickaël; Porcheron, Benoît; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2016-01-01

    Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. 14CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. PMID:26802041

  16. Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots.

    Science.gov (United States)

    Durand, Mickaël; Porcheron, Benoît; Hennion, Nils; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2016-03-01

    Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. (14)CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. © 2016 American Society of Plant Biologists. All Rights Reserved.

  17. Water relations and foliar isotopic composition of Prosopis tamarugo Phil. an endemic tree of the Atacama Desert growing under three levels of water table depth.

    Directory of Open Access Journals (Sweden)

    Marco eGarrido

    2016-03-01

    Full Text Available Prosopis tamarugo Phil. is a strict phreatophyte tree species endemic to the Pampa del Tamarugal, Atacama Desert. The extraction of water for various uses has increased the depth of the water table in the Pampa aquifers threatening its conservation. This study aimed to determine the effect of the groundwater table depth on the water relations of P. tamarugo and to present thresholds of groundwater depth (GWD that can be used in the groundwater management of the P. tamarugo ecosystem. Three levels of GWD, 11.2 ± 0.3 m, 10.3 ± 0.3 m and 7.1 ± 0.1 m, (the last GWD being our reference were selected and groups of 4 individuals per GWD were studied in the months of January and July of the years 2011 through 2014. When the water table depth exceeded 10 m, P. tamarugo had lower pre-dawn and midday water potential but no differences were observed in minimum leaf stomatal resistance when compared to the condition of 7.1 m GWD; the leaf tissue increased its δ13C and δ18O composition. Furthermore, a smaller green canopy fraction of the trees and increased foliage loss in winter with increasing water table depth was observed. The differences observed in the physiological behavior of P. tamarugo trees, attributable to the ground water depth; show that increasing the depth of the water table from 7 to 11 m significantly affects the water status of P. tamarugo. The results indicate that P. tamarugo has an anisohydric stomatal behaviour and that given a reduction in water supply it regulates the water demand via foliage loss. The growth and leaf physiological activities are highly sensitive to GWD. The foliage loss appears to prevent the trees from reaching water potentials leading to complete loss of hydraulic functionality by cavitation. The balance achieved between water supply and demand was reflected in the low variation of the water potential and of the variables related to gas exchange over time for a given GWD. This acclimation capacity of P

  18. Analysis of runoff sources and water uptake by trees using isotopic data in a small forested catchment

    Science.gov (United States)

    Mantese, N.; Penna, D.; Zuecco, G.; Borga, M.; Anfodillo, T.; Carraro, V.; Dalla Fontana, G.

    2012-04-01

    Plant transpiration is an important component of the hydrological cycle. Particularly, in densely vegetated areas, climatic and land-use changes might have significant hydrological (and ecological) implications. This leads to the need to identify the main water sources for tree transpiration and to evaluate how the flux exchanges between soil, vegetation and atmosphere possibly affect the runoff response of forested watersheds. Specifically, this study took advantage of the natural presence of water stable isotopes in the hydrological cycle to assess: i) the sources of water uptake by trees, and ii) the origin of water contributing to runoff in a small and densely forested catchment in the Italian Pre-Alps. Field surveys were carried out during late summer and early autumn of 2011 in the Ressi catchment (1.9 ha, North-Eastern Italy, mean elevation of 660 m a.s.l.). Beeches, chestnuts, maples and hazels represent the main tree species in the area, with sparse presence of hornbeams and ashes. Stream water stage, soil moisture at 0-30 cm depth at four locations, and water table level at three locations were continuously recorded. Bulk precipitation was collected from plastic bottles sealed with mineral oil and weekly manual sampling of stream water, soil water (by means of suction cups), groundwater and water in the xylem conduits (sap) from six beeches was performed for isotopic analyses. Sap was extracted in situ from beech twigs by using a pressure bomb. The isotopic composition of liquid samples (δ2H and δ18O) was determined by laser absorption spectroscopy. Additionally, water electrical conductivity was measured in the field (only for stream water, groundwater and rainfall) by a portable conductivity meter. Preliminary results showed a marked difference in the tracer concentration among the various water components in the catchment. Particularly, the average isotopic signal of tree water (-38.1 per mil δ2H and -5.95 δ18O) was statistically similar to soil

  19. Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

    Science.gov (United States)

    Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

    2016-10-01

    There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Silicon improves seed germination and alleviates oxidative stress of bud seedlings in tomato under water deficit stress.

    Science.gov (United States)

    Shi, Yu; Zhang, Yi; Yao, Hejin; Wu, Jiawen; Sun, Hao; Gong, Haijun

    2014-05-01

    The beneficial effects of silicon on plant growth and development under drought have been widely reported. However, little information is available on the effects of silicon on seed germination under drought. In this work, the effects of exogenous silicon (0.5 mM) on the seed germination and tolerance performance of tomato (Solanum lycopersicum L.) bud seedlings under water deficit stress simulated by 10% (w/v) polyethylene glycol (PEG-6000) were investigated in four cultivars ('Jinpengchaoguan', 'Zhongza No.9', 'Houpi L402' and 'Oubao318'). The results showed that the seed germination percentage was notably decreased in the four cultivars under water stress, and it was significantly improved by added silicon. Compared with the non-silicon treatment, silicon addition increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the production of superoxide anion (O2·) and hydrogen peroxide (H2O2) in the radicles of bud seedlings under water stress. Addition of silicon decreased the total phenol concentrations in radicles under water stress, which might contribute to the decrease of peroxidase (POD) activity, as observed in the in vivo and in vitro experiments. The decrease of POD activity might contribute to a less accumulation of hydroxyl radical (·OH) under water stress. Silicon addition also decreased the concentrations of malondialdehyde (MDA) in the radicles under stress, indicating decreased lipid peroxidation. These results suggest that exogenous silicon could improve seed germination and alleviate oxidative stress to bud seedling of tomato by enhancing antioxidant defense. The positive effects of silicon observed in a silicon-excluder also suggest the active involvement of silicon in biochemical processes in plants. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  1. Phenotypic response of Lycopersicon chilense to water deficit Respuesta fenotípica de Lycopersicon chilense al deficit hídrico

    Directory of Open Access Journals (Sweden)

    CARLOS MALDONADO

    2003-03-01

    Full Text Available ABSTRACT Environmental-induced phenotypic variation in plants is often considered to be a functional response that maximizes fitness in heterogeneous environments. Lycopersicon chilense, a tomato species endemic to Atacama Desert, shows altitudinal phenotypics variations in their natural environments, which could be due to different soil water availabilities. It is hypothesized that (a seeds coming from populations of different environments, cultivated in the same environment, will have similar phenotypes, if populations are not genetically differentiated, and that (b the different populations subjected to two drought levels should vary their phenotypic constitution with respect to the control groups. The responses of twenty phenotypic traits to different irrigation levels were studied in nine wild populations of Lycopersicon chilense. Seeds were collected from populations along an altitudinal gradient (from 20 m to 3,075 m, transferred to a common environment and grown under three soil water conditions: low (80 % FC, moderate (40 % FC and severe (20 % FC. In spite of the climatic differences in their natural habitat the phenotypic responses of plants growing in the same environment was similar in the nine populations. Significant differences among populations were only observed in three out of twenty traits (fruit fresh weight, fruit volume and number of seeds per fruit. Soil water deficit induced a phenotypic response in twelve characters; among these: root dry weight, cover, number of seeting fruits and number of seeds per fruit showed the highest significance. An interaction between population and drought treatment was found only for fresh weight of fruits, fruit volume and number of seeds per fruit. Our data indicate that the phenotypic response does not differ among populations growing under similar environmental conditions. Probably the phenotypic response of L. chilense in their natural habitats is related to physiological and metabolic

  2. Transpiration response of upland rice to water deficit changed by different levels of eucalyptus biochar

    Directory of Open Access Journals (Sweden)

    Rogério Gomes Pereira

    2012-05-01

    Full Text Available The objective of this work was to evaluate the effect of eucalyptus biochar on the transpiration rate of upland rice 'BRSMG Curinga' as an alternative means to decrease the effect of water stress on plant growth and development. Two-pot experiments were carried out using a completely randomized block design, in a split-plot arrangement, with six replicates. Main plots were water stress (WS and no-water stress (NWS, and the subplots were biochar doses at 0, 6, 12 and 24% in growing medium (sand. Total transpirable soil water (TTSW, the p factor - defined as the average fraction of TTSW which can be depleted from the root zone before water stress limits growth -, and the normalized transpiration rate (NTR were determined. Biochar addition increased TTSW and the p factor, and reduced NTR. Consequently, biochar addition was able to change the moisture threshold (p factor of the growing medium, up to 12% maximum concentration, delaying the point where transpiration declines and affects yield.

  3. Transpirative Deficit Index (TDI) for the management of water scarcity in irrigated areas: development and application in northern Italy

    Science.gov (United States)

    Borghi, Anna; Facchi, Arianna; Rienzner, Michele; Gandolfi, Claudio

    2016-04-01

    In Europe, the monitoring and assessment of drought is entrusted to the European Drought Observatory (EDO). EDO indicators are calculated considering rainfed agriculture and delivered on a 5 km grid. However, in southern Europe, irrigation may compensate for potentially severe agricultural droughts and specific water scarcity indicators that explicitly consider irrigation are needed. In the Po River Plain, irrigated crops cover more than 70% of the agricultural land, massive amounts of water are diverted from rivers for irrigation, and surface irrigation methods are largely applied. Nowadays, the region is not a water scarce basin, but irrigation water shortages have occurred with increased frequency during the last two decades. Moreover, a recent EU report shows that the Po River Plain is included among areas in Europe that by 2030 shall be affected by water scarcity. In this context, a study was started to select and develop indicators for the management and prevention of Water Scarcity and Drought (WS&D) based on the synergic use of hydrological modelling and Earth Observation data applied at a spatial scale of interest for end-users (250m grid). These indicators shall be better suited for the assessment of WS&D in Italy as well as in other southern European countries. This work presents the development and the application of the TDI (Transpirative Deficit Index) to a study area, within the Po River Plain. TDI is an agricultural drought index based on the transpiration deficit (TDx, calculated as the difference between potential and actual transpiration), computed by the spatially distributed hydrological model IDRAGRA and cumulated over a period of x days. TDx for each day of a specific year is compared to the long-term TDx probability distribution (e.g., over 20-30 years), which is transformed into a standardized normal distribution. The non-exceedance probability of TDx is finally expressed in terms of unit of standard deviation (TDI), following the approach

  4. Irrigation response and water productivity of deficit to fully irrigated spring camelina

    Science.gov (United States)

    Camelina [Camelina sativa L. Crantz] is an oil seed crop that could be adapted to the northern High Plains of the USA as a biofuel crop. Decreased ground water allocations in Nebraska necessitated determining the impact of limited irrigation on camelina. The objective of this research was to determi...

  5. Effect of the organic matter and soil water deficit on the castor bean inflorescences emission

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Rogerio Dantas de; Araujo, Ester Luiz de; Nascimento, Elka Costa Santos; Barros Junior, Genival [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Guerra, Hugo O. Carvallo; Chaves, Lucia Helena G. [Universidade Federal de Campina Grande (UAEAg/UFCG), PB (Brazil). Unidade Academica de Engenharia Agricola

    2008-07-01

    The castor bean culture has become important due to the several applications of its oil, which constitutes one of the best row materials for biodiesel manufacturing, and the base for several other industrial products. The objective of the present work was to study the effect of different soil water and soil organic matter on the castor bean inflorescence emission. The experiment was conducted from April to August 2006 under Greenhouse conditions using a randomized block 2x4 factorial design with two soil organic mater content (5.0 g.kg{sup -1} e 25.0 g.kg{sup -1}), four levels of available water (100, 90, 80 e 70% ) and three replicates. For this, 24 plastic containers, 75 kg capacity, were used on which was grown one plant 120 days after the seedling. When flowering occurred it was measured the number, the time required for the emission and the height of the emissions. The results were analyzed statistically; for the qualitative factor (with and without organic matter) the treatment means were compared through the Tukey test. For the quantitative ones (water levels) regressions were used. The time for the emission of the inflorescences was affected significantly by the organic matter and the available soil water content for plants. The number of inflorescences was affected positively by both treatments. (author)

  6. Influence of the organic matter and soil water deficit on the castor bean absolute growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Rogerio Dantas de; Guerra, Hugo O. Carvallo; Chaves, Lucia Helena G. [Universidade Federal de Campina Grande (UAEAg/UFCG), PB (Brazil). Unidade Academica de Engenharia Agricola; Araujo, Ester Luiz de; Nascimento, Elka Costa Santos; Barros Junior, Genival [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    Even when under low precipitations conditions, the castor bean production decrease, it constitutes a very good alternative. It has an elevated economical importance, because from the plant it is used their leaves, stem and seeds. From the stem it is obtained cellulose for the paper industry, from the leaves textile products and from the seeds oil and tort. The oil is the only glycerin soluble in alcohol and the base for several industrial products such as the biodiesel. The objective of the present work was to study the effect of different soil water and soil organic matter on the castor bean, BRS 188 cultivar rate growth. The experiment was conducted from April to August 2006 under greenhouse conditions using a randomized block 2x4 factorial design with two soil organic mater content (5.0 g.kg{sup -1} e 25.0 g.kg{sup -1}), four levels of available water (100, 90, 80 e 70% ) and three replicates. For this, 24 plastic containers, 75 kg capacity, were used on which was grown one plant 120 days after the seedling. At regular intervals the plant height was measured and the results analyzed statistically. For the qualitative treatments (with and without organic matter) the treatment means were compared through the Tukey test. For the quantitative ones (water levels) regressions were used. It was observed that both, organic matter and available water for plants proportionated benefit effects to the growth rate of the plant. (author)

  7. Yield, irrigation response, and water productivity of deficit to fully irrigated spring canola

    Science.gov (United States)

    Canola (Brassica napus) is an oil-seed crop that is adapted to the northern High Plains of the USA and is considered a viable rotational and biofuel crop. However, decreased ground water allocations have necessitated determining the impact of limited irrigation on canola productivity. The objectives...

  8. Effects of TiO2 nanoparticles and water-deficit stress on morpho-physiological characteristics of dragonhead (Dracocephalum moldavica L. plants

    Directory of Open Access Journals (Sweden)

    Hamid Mohammadi

    2016-10-01

    Full Text Available Water-deficit stress is the most important environmental factors limiting plant growth, and production. Nano-titanium dioxide (nano anataseTiO2 can have various profound effects on the crop physiological, biochemical and morphological characteristics. In the present research, the influences of different concentrations ofTiO2 nanoparticles (NPs (0, 10 and 40 ppm and water-deficit stress on Dragonhead (Dracocephalum moldavica L. were investigated in a factorial experiment based on randomized complete block design with three replications. Results showed that under normal irrigation, foliar application of 10 ppm TiO2 NPs increased plant shoot dry mass and essential oils content. Under water-deficit stress condition, plants treated with 10 ppm TiO2 NPs had more proline and much less H2O2 and malondialdehyde content as compared to untreated plants. Therefore, it can be concluded that proper concentration of TiO2 NPs probably can be used as an exogenous stimuli for improvement of shoot growth and essential oil content in plants. Furthermore, water-deficit stress-induced damages such as oxidative stress and membrane damage can be ameliorated by foliar application of TiO2 NPs at appropriate concentrations.

  9. Diel trends in stomatal response to ozone and water deficit: a unique relationship of midday values to growth and allometry in Pima cotton?

    Science.gov (United States)

    D. A. Grantz; R. Paudel; H.-B. Vu; A. Shrestha; Nancy Grulke; L. J. De Kok

    2015-01-01

    Plant responses to ozone (O3) and water deficit (WD) are commonly observed, although less is known about their interaction. Stomatal conductance (gs) is both an impact of these stressors and a protective response to them. Stomatal closure reduces inward flux of O3 and outward flux...

  10. Seasonal scale water deficit forecasting in Africa and the Middle East using NASA's Land Information System (LIS)

    Science.gov (United States)

    Shukla, Shraddhanand; Arsenault, Kristi R.; Getirana, Augusto; Kumar, Sujay V.; Roningen, Jeanne; Zaitchik, Ben; McNally, Amy; Koster, Randal D.; Peters-Lidard, Christa

    2017-04-01

    Drought and water scarcity are among the important issues facing several regions within Africa and the Middle East. A seamless and effective monitoring and early warning system is needed by regional/national stakeholders. Such system should support a proactive drought management approach and mitigate the socio-economic losses up to the extent possible. In this presentation, we report on the ongoing development and validation of a seasonal scale water deficit forecasting system based on NASA's Land Information System (LIS) and seasonal climate forecasts. First, our presentation will focus on the implementation and validation of the LIS models used for drought and water availability monitoring in the region. The second part will focus on evaluating drought and water availability forecasts. Finally, details will be provided of our ongoing collaboration with end-user partners in the region (e.g., USAID's Famine Early Warning Systems Network, FEWS NET), on formulating meaningful early warning indicators, effective communication and seamless dissemination of the monitoring and forecasting products through NASA's web-services. The water deficit forecasting system thus far incorporates NOAA's Noah land surface model (LSM), version 3.3, the Variable Infiltration Capacity (VIC) model, version 4.12, NASA GMAO's Catchment LSM, and the Noah Multi-Physics (MP) LSM (the latter two incorporate prognostic water table schemes). In addition, the LSMs' surface and subsurface runoff are routed through the Hydrological Modeling and Analysis Platform (HyMAP) to simulate surface water dynamics. The LSMs are driven by NASA/GMAO's Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), and the USGS and UCSB Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) daily rainfall dataset. The LIS software framework integrates these forcing datasets and drives the four LSMs and HyMAP. The Land Verification Toolkit (LVT) is used for the evaluation of the

  11. Agroforestry in temperate regions: where does the water go? A case study with ERT in a corn field bordered by poplar trees.

    Science.gov (United States)

    Maloteau, Sophie; Coussement, Tom; Pardon, Paul; Artru, Sidonie; Javaux, Mathieu; Garré, Sarah

    2017-04-01

    Recently, agroforestry systems have been recognized to provide an opportunity for "ecological intensification", thereby increasing yield outcome while simultaneously minimizing negative impacts on the environment. Mixtures of trees and crops have the potential to capture more resources of light, water and nutrients than monocultures of trees or crops (Cannell et al. 1996). Nevertheless, few studies are available focusing on the impact of trees on soil moisture dynamics in cropped soil in temperate regions. In this study, we monitored the soil water dynamics in a corn field bordered by poplar trees in Ieper, Belgium using Electrical resistivity tomography (ERT) and classical soil tension sensors (Watermark) during the entire growing season of 2016 (May-September). We installed four ERT transects of 30 m long with an electrode spacing of 50cm. Three transects were placed in a part of the field bordered by trees and one reference transect was located in a part of the field without trees. Next to each transect, Watermark sensors were installed to estimate the soil water tension. The data allow us to monitor the influence of the trees on the soil water depletion by the crop. Preliminary results show a marked effect of the trees on the measured resistivity distribution, which corresponds to observed patterns in plant growth.

  12. Nitrogen cycling: water use efficiency interactions in semi-arid ecosystems in relation to management of tree legumes (Prosopis)

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.; Clark, P.R.; Osborn, J.; Cannell, G.H.

    1980-04-01

    Plant productivity in semi-arid ecosystems is often limited by soil fertility as much as it is by moisture availability. A quantitative assessment of nitrogen limitations on water use efficiency has been made after careful review of plant water use efficiency data at high and low soil fertilities and after careful review of nitrogen inputs to semi arid ecosystems in the form of: blue-green algae-lichen crusts; non-symbiotic nitrogen fixers; rainfall; and tree legumes. This analysis indicates that plant productivity in semi-arid regions may be 10 fold more limited by nitrogen than moisture availability. Forage yields of non-nitrogen fixing trees and shrubs could be greatly increased by interplanting with drought adapted nitrogen fixers such as Prosopis and Acacia. Calculations based on water use efficiencies of annual legumes and nitrogen fixation values of tree legumes predict that well managed, spaced, and cared for orchards of specially selected Prosopis could produce 4000 Kgha/sup -1/ yr/sup -1/ of 13% protein pods at 500 mm annual rainfall with only light fertilization with phosphate, potassium and sulfur. Field measurements of pod yields for 25 selections of 3 year old Prosopis grown under managed orchard conditions in southern California are presented. Spacing regimes and harvesting techniques for Prosopis are proposed to facilitate pod production.

  13. Monitoring of sap flow, leaf water potential, stomatal conductance, and latex yield of rubber trees under irrigation management

    Directory of Open Access Journals (Sweden)

    Prapaporn Tongsawang

    2008-08-01

    Full Text Available To investigate the physiological responses and latex yield of rubber trees under irrigation management, an experiment was established at Songkhla Province, southern Thailand. The sap flow of rubber trees was measured by heat-pulse technique. First, the anatomy of sapwood and the optimum depth for implanting the sap flow sensor probe were determined. Then, the diurnal changes of the physiological responses (sap flow, leaf water potential, and stomatal conductance and latex yield under three regimes of irrigation (T1: no irrigation, T2: irrigation at 1.0 crop evapotranspiration (ETc and T3: irrigation at0.5 ETc were determined. The results showed that xylem vessels in sapwood were homogeneous and the optimum depth for implanting the sap flow sensor probes was 10 mm beneath the cambium. In the measurements of diurnal changes of the physiological responses, it was found that stomatal conductance and sap flow rates were related to radiation. Sap flow and stomatal conductance increased from the morning to the midday. Then they decreased slowly during the afternoon. However,leaf water potential changes showed an opposite effect. Among the three treatments, the results showed that sap flow, leaf water potential and stomatal conductance in T2 were highest. The trees in T2 also exhibited the highest latex yield from April to July 2006, which was significantly different from those of T3 and T1. This implied that latex yield increased with an increase of sap flow.

  14. Empirical Constraints on Water Stress-induced Tree Mortality and its Impacts on Forest Biomass Dynamics in Western North America

    Science.gov (United States)

    Hember, R. A.; Kurz, W.; Coops, N. C.

    2015-12-01

    It is widely appreciated that forest biomass dynamics do not follow smooth sigmoidal age response functions, yet accounting for realistic overshoot-and-collapse cycles remains a big challenge. Here, millions of observations of vital status at permanent sample plots from Canada and the U.S. were used to predict probability of tree mortality (Pm) based on segmented logistic regression functions of xylem water potential (WPX) derived from a simplified model of plant water transport for dominant boreal and temperate North American tree species. First, we demonstrate that hydraulic limits are clearly detectable from the increase of Pm at the lowest levels of WPX and that the relationship is strongly defined by increasing vulnerability (decreasing WPX) as tree height (h) increases. Second, we demonstrate the implications of representing water stress-induced mortality on regional simulations of net ecosystem biomass production (NEBP), drawing on examples of specific collapse events where we have observations of NEBP for comparison. Simulations suggest that extreme surface energy balance anomalies during 1981 and 1998 triggered catastrophic levels of mortality in regions of western North America. Yet, simulations may still greatly underestimate the impact of these collapse events if associations exist between WPX and insect outbreaks. Nevertheless, the models suggest that a combination of size-dependent hydraulic limits and low-frequency variability in the surface energy balance conspire to produce overshoot-and-collapse cycles that strongly shaped biomass dynamics in western North America over recent decades.

  15. Effect of water stage and tree stand composition on spatiotemporal differentiation of spring water chemistry draining Carpathian flysch slopes (Gorce Mts).

    Science.gov (United States)

    Jasik, Michał; Małek, Stanisław; Żelazny, Mirosław

    2017-12-01

    The purpose of this study was to identify the factors affecting spring water chemistry in different tree stands and to measure the influence of water stage on the physicochemical parameters of spring waters in a small Carpathian catchment. Water samples were collected three times per year at various stages of the water: after the spring thaw, after a period of heavy rain and after a dry period in 2011 and 2012. Water samples were left in the laboratory to reach room temperature (19-20°C) and analyzed for EC (reference T=25°C) and pH. After filtration through 0.45μm PTFE syringe filters, the water samples were analyzed by means of ion chromatography using a DIONEX ICS 5000 unit. The following ions were analyzed: Ca2+, Mg2+, Na+, K+, HCO3-, SO42-, Cl-, and NO3-. Multivariate analysis (PCA) allowed the identification of two factors of spring water chemistry: factor 1, water stage and factor 2 tree stand composition. Seasonal variation of spring water chemistry showed that, higher pH values and mineralization as well as higher concentrations of Ca2+ and Mg2+ were measured during low water stage periods while lower EC and pH values were noted after spring snowmelt and rainfall, when higher concentrations of NO3- and SO42- were also found. Higher concentrations of Ca2+ and Mg2+ and higher pH of spring waters located in beech-fir stands and in those mixed with a large proportion of beech as well as a lower concentration of Ca2+, Mg2+ and HCO3-, pH, conductivity and mineralization of these spring waters, in which the alimentation areas were covered by upper subalpine spruce stands were noted. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. CHANGES IN LEVELS OF ACTIVITY OF SERINE PROTEASES ACCOMPANY THE EXPOSURE OF COMMON BEAN (PHASEOLUS VULGARIS L. TO WATER DEFICIT

    Directory of Open Access Journals (Sweden)

    M. Budič

    2008-09-01

    Full Text Available A wide variety of proteolytic enzymes exist in plants. On their levels depends protein turnover, a fundamental component in plant development and adaptation to environmental conditions. Cysteine proteases have frequently been reported to be influenced by drought, but only a few serine proteases (SP, among them the trypsin-like enzyme and two aminopeptidases from bean leaves (Bartels and Sunkar, 2005; Hieng et al., 2004. Our starting point was to identify proteolytic activities assigned to SPs that change with drought and then to characterize the corresponding proteases. A quantitative, analytical one-step method was used to separate endopeptidases and aminopeptidases active against a range of substrates in leaf extracts of plants grown in the field (FC. The influence of drought was determined for those of these activities which were confirmed as SPs, based on their inhibition by specific inhibitors. Under water deficit in plants grown under controlled conditions (CC their levels changed in different ways. The levels of SP activities in FC plants, observed during a period of relative drought, were similar to those measured in mildly stressed CC plants. The partial characterisations of some of these SPs will be presented. Our results point to a number of roles for different SPs in the plant response to water stress, which could range from enhanced protein turnover to limited proteolysis at specific sites.

  17. The effect of mycorrhizal fungi on malondialdehyde concentration and some metabolic processes in hyssop (Hyssopus officinalis under water deficit stress

    Directory of Open Access Journals (Sweden)

    Farogh Soleymani

    2015-06-01

    Full Text Available Ion balance and osmotic regulation in plants to mitigate the effects of drought is possible with accumulation of osmolytes like proline and glycine betaine. Accordingly, in order to investigate the effect of mycorrhizal fungai species on the eco-physiological characteristics of hyssop, a factorial experimental based on randomized complete block design with three replications was conducted at the Research Farm of Agriculture and Natural Resources of West Azarbaijan in 2013. Experimental treatments included species of mycorrhizal fungi (Glomus mosseae, G. intraradices, G. fasiculatum, G. claroideum, Acaulospora longula and control without mycorrhiza and four levels of irrigation (irrigation at 80, 70, 60 and 50% of field capacity. The results of ANOVA showed the significant interaction between water deficit and mycorrhizal fungi species on the concentrations of malondialdehyde (MDA, glycine betaine, proline, total soluble carbohydrates and essential oil percent. The highest concentrations of malondialdehyde (MDA (125 nmol/g fresh weight, glycine betaine (2019 μm/g dry weight, proline (111 μm/g fresh weight, essential oil percentage (7.29% and total soluble carbohydrates (396.7 mg/g dry weight were obtained from plants inoculated by G. claroideum, A. longula, A. longula, G. fasiculatum and G. claroideum and irrigated at 50 and 60% field capacity, respectively. The concentration of malondialdehyde (MDA biomarker was increased at non-mycorrhizal plants compared with mycorrhizal one. Overall, this study suggested that the mycorrhizal species were effective to reduce stress and water use efficiency.

  18. EnviroAtlas - Green Bay, WI - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  19. EnviroAtlas - Des Moines, IA - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, Forest is defined as Trees...

  20. EnviroAtlas - Milwaukee, WI - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  1. EnviroAtlas - Austin, TX - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, Forest is defined as Trees...

  2. EnviroAtlas - Woodbine, IA - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  3. EnviroAtlas - Pittsburgh, PA - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  4. EnviroAtlas - Memphis, TN - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). Forest is defined as Trees & Forest and Woody...

  5. EnviroAtlas - Tampa, FL - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  6. EnviroAtlas Tree Cover Configuration and Connectivity, Water Background Web Service

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). The 1-meter resolution tree...

  7. EnviroAtlas - Portland, ME - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  8. EnviroAtlas - New Bedford, MA - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  9. EnviroAtlas - Fresno, CA - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  10. EnviroAtlas - Phoenix, AZ - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  11. EnviroAtlas - Paterson, NJ - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  12. EnviroAtlas - Durham, NC - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is only trees &...

  13. EnviroAtlas - Portland, OR - Tree Cover Configuration and Connectivity, Water Background

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset categorizes forest land cover into structural elements (e.g. core, edge, connector, etc.). In this community, forest is trees & forest...

  14. Photochemical production of organic matter triplet states in water samples from mountain lakes, located below or above the tree line.

    Science.gov (United States)

    De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio; Brigante, Marcello; Mailhot, Gilles; Vione, Davide

    2012-08-01

    The production of triplet states (T(*)) of chromophoric dissolved organic matter (CDOM), reacting with the probe molecule 2,4,6-trimethylphenol (TMP) was measured upon irradiation of water samples, taken from lakes located in a mountain area (NW Italy) between 1450 and 2750 m above sea level. The lakes are located below or above the tree line and surrounded by different vegetation types (trees, alpine meadows or exposed rocks). The most photoactive samples belonged to lakes below the tree line and their fluorescence spectra and CDOM optical features suggested the presence of a relatively elevated amount of humic (allochthonous) material. The lowest (negligible) photoactivity was found for a lake surrounded by exposed rocks. Its CDOM showed an important autochthonous contribution (due to in-lake productivity) and considerably higher spectral slope compared to the other samples, suggesting low CDOM molecular weight and/or aromaticity. Among the samples, CDOM photoactivity (measured as the rate of TMP-reactive T(*) photoproduction) decreased with changing vegetation type in the order: trees, meadows, rocks. It could be connected with decreasing contribution from catchment runoff and increasing contribution from autochthonous processes and possibly precipitation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Differences in defence responses of Pinus contorta and Pinus banksiana to the mountain pine beetle fungal associate Grosmannia clavigera are affected by water deficit.

    Science.gov (United States)

    Arango-Velez, Adriana; El Kayal, Walid; Copeland, Charles C J; Zaharia, L Irina; Lusebrink, Inka; Cooke, Janice E K

    2016-04-01

    We tested the hypotheses that responses to the mountain pine beetle fungal associate Grosmannia clavigera will differ between the evolutionarily co-evolved host lodgepole pine (Pinus contorta var. latifolia) and the naïve host jack pine (Pinus banksiana) and that these responses will be influenced by water availability. G. clavigera inoculation resulted in more rapid stem lesion development in lodgepole than in jack pine; water deficit delayed lesion development in both species. Decreased hydraulic conductivity was observed in inoculated lodgepole pine seedlings, likely because of tracheid occlusion by fungal hyphae and/or metabolite accumulation. Drought but not inoculation significantly impacted bark abscisic acid levels. Jasmonic and salicylic acid were implicated in local and systemic responses of both species to G. clavigera, with salicylic acid appearing to play a greater role in jack pine response to G. clavigera than lodgepole pine. Water deficit increased constitutive levels and/or attenuated induced responses to G. clavigera for several monoterpenes in lodgepole but not jack pine. Instead, inoculation of well-watered but not water deficit jack pine resulted in a greater number of xylem resin ducts. These findings reveal mechanisms underlying differences in G. clavigera-induced responses between lodgepole and jack pine hosts, and how water availability modulates these responses. © 2015 John Wiley & Sons Ltd.

  16. Pricing rainbow, green, blue and grey water: tree cover and geopolitics of climatic teleconnections

    NARCIS (Netherlands)

    Noordwijk, van M.; Namirembe, S.; Catacutan, D.; Williamson, D.; Gebrekirstos, A.

    2014-01-01

    Atmospheric moisture (“rainbow water”) is the source of all green, blue and grey water flows. Current water-related legislation and policies have moved beyond blue (water allocation) and grey (waste water treatment) water concerns to incorporate the green water concept of additional water use by

  17. Water Deficit Effects on Raffinose Family Oligosaccharide Metabolism in Coleus1

    Science.gov (United States)

    Pattanagul, Wattana; Madore, Monica A.

    1999-01-01

    Variegated coleus (Coleus blumei Benth.) plants were exposed to a restricted water supply for 21 d. The relative water content in leaf tissues was reduced from 80% (control) to 60% (drought-stressed). Under drought conditions, the stomatal conductance and leaf photosynthetic rate were reduced. In green leaf tissues, drought stress also greatly decreased the diurnal light-period levels of the raffinose family oligosaccharides (RFOs) stachyose and raffinose, as well as those of other non-structural carbohydrates (galactinol, sucrose, hexoses, and starch). However, drought had little effect on soluble carbohydrate content of white, non-photosynthetic leaf tissues. In green tissues, galactinol synthase activity was depressed by drought stress. An accumulation of O-methyl-inositol was also observed, which is consistent with the induction of myoinositol-6-O-methyltransferase activity seen in the stressed green tissues. In source tissues, RFO metabolism is apparently reduced by drought stress through a combined effect of decreased photosynthesis and reduced galactinol synthase activity. Moreover, a further reduction in RFO biosynthesis may have been due to a switch in carbon partitioning to O-methyl-inositol biosynthesis, creating competition for myoinositol, a metabolite shared by both biochemical pathways. PMID:10557248

  18. Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

    Directory of Open Access Journals (Sweden)

    Ejaz Ahmad Waraich

    2017-05-01

    Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

  19. Soil Moisture/ Tree Water Status Dynamics in a Mid-Latitude Montane Forest, Southern Sierra Critical Zone Observatory, CA

    Science.gov (United States)

    Hartsough, P. C.; Malazian, A.; Kamai, T.; Roudneva, E.; Hopmans, J. W.

    2009-12-01

    In the Mediterranean climate of the Sierra Nevada, snow pack persists well into the spring after precipitation has effectively stopped. With the onset of summer and continued dry conditions, snow quickly melts, and soil profiles dry out as shrubs and trees deplete the available soil moisture. A better understanding of surface and subsurface water budgets in remote landscapes warrants closer monitoring of moisture and temperature variability in near surfaces soils. As part of the Southern Sierra Critical Zone Observatory (CZO), investigators from University of California deployed approximately 150 soil moisture, water potential and temperature sensors within the root structure of an individual white fir tree (Abies concolor) located in the Kings River Experimental Watershed (KREW). These sensors complement sap flow measurements in the trunk, stem water potential measurements in the canopy, and snow depth measurements, to enable the Southern Sierra CZO researchers to investigate how soil environmental stresses (water, temperature, and nutrients) impact forest ecosystems across the rain-to-snow-dominated transition zone. We captured the dynamics of the soil profile desiccation at various depths beneath the snow pack as soils went from wet to very dry conditions. Monitoring of sap flow and periodic leaf water potential measurements, we tracked the activity of the tree as it responded to changing available moisture in the root zone. All sensors were reactive to moisture and temperature variations and showed dynamic responses to precipitation, snow melt and changes in vegetative demand. We demonstrate here the initial phase of a multi-year deployment of soil moisture sensors as a critical integrator of hydrologic/ biotic interaction in a forested catchment as part of a wider effort to document changing ecosystem response to changing environmental inputs.

  20. Water-Deficit Tolerance in Sweet Potato [Ipomoea batatas (L.) Lam.] by Foliar Application of Paclobutrazol: Role of Soluble Sugar and Free Proline

    Science.gov (United States)

    Yooyongwech, Suravoot; Samphumphuang, Thapanee; Tisarum, Rujira; Theerawitaya, Cattarin; Cha-um, Suriyan

    2017-01-01

    The objective of this study was to elevate water deficit tolerance by improving soluble sugar and free proline accumulation, photosynthetic pigment stabilization, photosynthetic abilities, growth performance and storage root yield in sweet potato cv. ‘Tainung 57’ using a foliar application of paclobutrazol (PBZ). The experiment followed a Completely Randomized Block Design with four concentrations of PBZ: 0 (control), 17, 34, and 51 μM before exposure to 47.5% (well irrigation), 32.3% (mild water deficit) or 17.5% (severe water deficit) soil water content. A sweet potato cultivar, ‘Japanese Yellow’, with water deficit tolerance attributes was the positive check in this study. Total soluble sugar content (sucrose, glucose, and fructose) increased by 3.96-folds in ‘Tainung 57’ plants treated with 34 μM PBZ grown under 32.3% soil water content (SWC) compared to the untreated plants, adjusting osmotic potential in the leaves and controlling stomatal closure (represented by stomatal conductance and transpiration rate). In addition, under the same treatment, free proline content (2.15 μmol g-1 FW) increased by 3.84-folds when exposed to 17.5% SWC. PBZ had an improved effect on leaf size, vine length, photosynthetic pigment stability, chlorophyll fluorescence, and net photosynthetic rate; hence, delaying wilting symptoms and maintaining storage root yield (26.93 g plant-1) at the harvesting stage. A positive relationship between photon yield of PSII (ΦPSII) and net photosynthetic rate was demonstrated (r2 = 0.73). The study concludes that soluble sugar and free proline enrichment in PBZ-pretreated plants may play a critical role as major osmoprotectant to control leaf osmotic potential and stomatal closure when plants were subjected to low soil water content, therefore, maintaining the physiological and morphological characters as well as storage root yield. PMID:28848596

  1. Water-Deficit Tolerance in Sweet Potato [Ipomoea batatas (L. Lam.] by Foliar Application of Paclobutrazol: Role of Soluble Sugar and Free Proline

    Directory of Open Access Journals (Sweden)

    Suravoot Yooyongwech

    2017-08-01

    Full Text Available The objective of this study was to elevate water deficit tolerance by improving soluble sugar and free proline accumulation, photosynthetic pigment stabilization, photosynthetic abilities, growth performance and storage root yield in sweet potato cv. ‘Tainung 57’ using a foliar application of paclobutrazol (PBZ. The experiment followed a Completely Randomized Block Design with four concentrations of PBZ: 0 (control, 17, 34, and 51 μM before exposure to 47.5% (well irrigation, 32.3% (mild water deficit or 17.5% (severe water deficit soil water content. A sweet potato cultivar, ‘Japanese Yellow’, with water deficit tolerance attributes was the positive check in this study. Total soluble sugar content (sucrose, glucose, and fructose increased by 3.96-folds in ‘Tainung 57’ plants treated with 34 μM PBZ grown under 32.3% soil water content (SWC compared to the untreated plants, adjusting osmotic potential in the leaves and controlling stomatal closure (represented by stomatal conductance and transpiration rate. In addition, under the same treatment, free proline content (2.15 μmol g-1 FW increased by 3.84-folds when exposed to 17.5% SWC. PBZ had an improved effect on leaf size, vine length, photosynthetic pigment stability, chlorophyll fluorescence, and net photosynthetic rate; hence, delaying wilting symptoms and maintaining storage root yield (26.93 g plant-1 at the harvesting stage. A positive relationship between photon yield of PSII (ΦPSII and net photosynthetic rate was demonstrated (r2 = 0.73. The study concludes that soluble sugar and free proline enrichment in PBZ-pretreated plants may play a critical role as major osmoprotectant to control leaf osmotic potential and stomatal closure when plants were subjected to low soil water content, therefore, maintaining the physiological and morphological characters as well as storage root yield.

  2. Black plastic mulch combined with summer cover crop increases the yield and water use efficiency of apple tree on the rainfed Loess Plateau.

    Science.gov (United States)

    Zheng, Wei; Wen, Meijuan; Zhao, Zhiyuan; Liu, Jie; Wang, Zhaohui; Zhai, Bingnian; Li, Ziyan

    2017-01-01

    Water deficit significantly limits dryland rainfed fruit production, so increasing water conservation is crucial for improving fruit productivity in arid and semiarid areas. In this study, we tested two treatments in an apple orchard: 1) PC treatment comprising black plastic mulch (BPM) (in-row) with weed control (inter-row); 2) and PGC treatment comprising BPM (in-row) combined with a summer cover crop (inter-row) of rape (Brassica campestris L.), which was sown in mid-June and was living from July to September. Under PGC, the inter-row soil water storage increased by 17.9% and 11.5% compared with PC after the harvest in 2013 and 2014, respectively, but there was no significant increase in 2015. The evapotranspiration (ET) from the inter-row areas during the cover crop period was lower under PGC than PC in 2013 (19.6%), 2014 (11.3%), and 2015 (13.3%). However, the differences in the total ET from the inter-row areas between the two treatments were not obvious, and the total ET from in-row areas was higher under PGC than PC due to the increased water uptake by apple trees under PGC. The apple yield, water use efficiency during the cover crop period (WUEg) and total water use efficiency (WUE) fluctuated during the experimental years. Compared with PC, the apple yield increased by 14.1%, 18.8%, and 26.7% under PGC in 2013, 2014, and 2015, respectively. In addition, the WUEg was 26.4%, 24.7%, and 32.7% higher under PGC compared with PC in 2013, 2014, and 2015, respectively. Thus, the WUE under PGC was 13.8% and 11.7% higher than that under PC in 2013 and 2014, respectively, but the difference was not significant in 2015 (p = 0.0527). Thus, BPM combined with a summer cover crop is recommended for decreasing the summer ET and promoting apple production in rainfed dryland areas where the rainy season is usually the hot season.

  3. Role of six European tree species and land-use legacy for nitrogen and water budgets in forests

    DEFF Research Database (Denmark)

    Riis Christiansen, Jesper; Vesterdal, Lars; Callesen, Ingeborg

    2010-01-01

    Water and nutrient fluxes for single stands of different tree species have been reported in numerous studies, but comparative studies of nutrient and hydrological budgets of common European deciduous tree species are rare. Annual fluxes of water and inorganic nitrogen (N) were established in a 30...... in Denmark, Mattrup and Vallø during 2 years. Mean annual percolation below the root zone (mm yr−1±SE, n=4) ranked in the following order: maple (351±38)>lime (284±32), oak (271±25), beech (257±30), ash (307±69)≫ spruce (75±24). There were few significant tree species effects on N fluxes. However, the annual...... mean N throughfall flux (kg N ha−1 yr−1±SE, n=4) for spruce (28±2) was significantly larger than for maple (12±1), beech (11±1) and oak (9±1) stands but not different from that of lime (15±3). Ash had a low mean annual inorganic N throughfall deposition of 9.1 kg ha−1, but was only present at Mattrup...

  4. Application of time-lapse ERT to characterize soil-water-disease interactions of young citrus trees

    Science.gov (United States)

    Peddinti, S. R.; Kbvn, D. P.; Ranjan, S.; R M, P. G.

    2016-12-01

    Vidarbha region in Maharashtra, India is witnessing a continuous decrease in orange crop due to the propagation of `Phytopthora root rot', a water mold disease. Under favorable conditions, the disease causing bacteria can attack the plant root system and propagates to the surface (where first visual impression is made), making difficult to regain the plant health. This research aims at co-relating eco-hydrological fluxes with disease sensing parameters of orange trees. Two experimental plots around a healthy-young and declined-young orange trees were selected for our analysis. A 3-dimentional electrical resistivity tomography (ERT) (Figure) was carried at each plot to quantify the soil moisture distribution at a vadose zone. Pedo-electric relations were obtained considering modified Archie's law parameters. ERT derived moisture data was validated with time domain reflectometry (TDR) point observations. Soil moisture profiles derived from ERT were observed to be differ marginally between the two plots. Disease quantification was done by estimating the density of Phytopthora spp. inoculum in soils sampled along the root zone. Identification of Phytopthora spp. was done in the laboratory using taxonomic and morphologic criteria of the colonies. Spatio-temporal profiles of soil moisture and inoculum density were then co-related to comment on the eco-hydrological fluxes contributing to the health propagation of root rot in orange tree for implementing effective water management practices.

  5. Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions.

    Science.gov (United States)

    Lévesque, Mathieu; Siegwolf, Rolf; Saurer, Matthias; Eilmann, Britta; Rigling, Andreas

    2014-07-01

    Higher atmospheric CO2 concentrations (c(a)) can under certain conditions increase tree growth by enhancing photosynthesis, resulting in an increase of intrinsic water-use efficiency (i WUE) in trees. However, the magnitude of these effects and their interactions with changing climatic conditions are still poorly understood under xeric and mesic conditions. We combined radial growth analysis with intra- and interannual δ(13)C and δ(18)O measurements to investigate growth and physiological responses of Larix decidua, Picea abies, Pinus sylvestris, Pinus nigra and Pseudotsuga menziesii in relation to rising c(a) and changing climate at a xeric site in the dry inner Alps and at a mesic site in the Swiss lowlands. (i)WUE increased significantly over the last 50 yr by 8-29% and varied depending on species, site water availability, and seasons. Regardless of species and increased (i)WUE, radial growth has significantly declined under xeric conditions, whereas growth has not increased as expected under mesic conditions. Overall, drought-induced stomatal closure has reduced transpiration at the cost of reduced carbon uptake and growth. Our results indicate that, even under mesic conditions, the temperature-induced drought stress has overridden the potential CO2 'fertilization' on tree growth, hence challenging today's predictions of improved forest productivity of temperate forests. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  6. Screening for drought tolerance: comparison of maize hybrids under water deficit condition

    Directory of Open Access Journals (Sweden)

    Qurban Ali

    2016-02-01

    Full Text Available Background: Maize is an important cereal crop, grown throughout the globe for human food and livestock feed, but biotic and abiotic factors had shown adverse effects on biomass and grain yield. Changing climatic conditions have imposed drought (water scarcity as a major problem to combat with yield losses and biomass in maize and other cereals. Methods: The prescribed study was conducted to evaluate F1 hybrids at seedling subject to 45% moisture level. The data was recorded and subjected to multivariate analysis to find the significant variation attributed by various traits under stress conditions for efficient root/shoot development. Results: Significant differences were found in F1 hybrids for all studied traits. Higher heritability was found for root length, shoot length and fresh shoot weight, while fresh shoot weight, dry shoot weight and dry root weight showed higher genetic advance. Significant correlation was found for dry root weight to fresh shoot length and fresh root length, fresh root weight to fresh root/shoot weight ratio and fresh shoot weight. The hybrids Sh-139×B-316, Raka-poshi×B-316, B-327×B-316, Sh-139×EV-340, EV-1097Q×EV-347, EV-1097Q×EV-340, EV-1097Q×Pop/209 and B-327×EV-340 showed higher and positive heterosis and heterobeltiosis for most of the studied traits. To assess the overall variation on dependent structure, we used multivariate analysis, an important tool in breeding program, for efficient selection. Conclusions: EV-1097Q×Pop/209 and Sh-139×EV-340 showed significant results for root and shoot development under various water stress regimes at seedling stage, thus further studies should be carried out to find out the known and un-known loci regarding root and shoot development traits in high yielding maize cultivars under arid/semi-arid regions.

  7. Analysis of carbohydrates in Lupinus albus stems on imposition of water deficit, using porous graphitic carbon liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Antonio, Carla; Pinheiro, Carla; Chaves, Maria Manuela; Ricardo, Cândido Pinto; Ortuño, Maria Fernanda; Thomas-Oates, Jane

    2008-04-11

    This work reports the development and application of a negative ion mode online LC-ESI-MS method for studying the effect of water deficit on the carbohydrate content of Lupinus albus stems, using a porous graphitic carbon (PGC) stationary phase and an ion trap mass spectrometer. Using this method, separation and detection of several water soluble carbohydrates, ranging from mono-, di-, and oligosaccharides (raffinose, stachyose, and verbascose) to sugar alcohols was achieved in approximately 10 min. This on-line PGC-LC-ESI-MS method shows good linearity with correlation coefficients R(2)>0.99, selectivity, short analysis time, and limits of detection (LOD) ranging from 0.4 to 9 pmol for sugars and 4-20 pmol for sugar alcohols. This PGC-LC-ESI-MS method is sensitive and allowed us to detect even small alterations in carbohydrate levels in L. albus stems that resulted from a mild/early water deficit (nmol g(-1)DW). This paper describes details of our method and its application to the quantitative analysis of water soluble underivatised carbohydrates extracted from L. albus stem tissues that have been subjected to early and severe water deficit conditions, followed by a rewatering period.

  8. A biophysical approach using water deficit factor for daily estimations of evapotranspiration and CO2 uptake in Mediterranean environments

    Science.gov (United States)

    Helman, David; Lensky, Itamar M.; Osem, Yagil; Rohatyn, Shani; Rotenberg, Eyal; Yakir, Dan

    2017-09-01

    Estimations of ecosystem-level evapotranspiration (ET) and CO2 uptake in water-limited environments are scarce and scaling up ground-level measurements is not straightforward. A biophysical approach using remote sensing (RS) and meteorological data (RS-Met) is adjusted to extreme high-energy water-limited Mediterranean ecosystems that suffer from continuous stress conditions to provide daily estimations of ET and CO2 uptake (measured as gross primary production, GPP) at a spatial resolution of 250 m. The RS-Met was adjusted using a seasonal water deficit factor (fWD) based on daily rainfall, temperature and radiation data. We validated our adjusted RS-Met with eddy covariance flux measurements using a newly developed mobile lab system and the single active FLUXNET station operating in this region (Yatir pine forest station) at a total of seven forest and non-forest sites across a climatic transect in Israel (280-770 mm yr-1). RS-Met was also compared to the satellite-borne MODIS-based ET and GPP products (MOD16 and MOD17, respectively) at these sites.Results show that the inclusion of the fWD significantly improved the model, with R = 0.64-0.91 for the ET-adjusted model (compared to 0.05-0.80 for the unadjusted model) and R = 0.72-0.92 for the adjusted GPP model (compared to R = 0.56-0.90 of the non-adjusted model). The RS-Met (with the fWD) successfully tracked observed changes in ET and GPP between dry and wet seasons across the sites. ET and GPP estimates from the adjusted RS-Met also agreed well with eddy covariance estimates on an annual timescale at the FLUXNET station of Yatir (266 ± 61 vs. 257 ± 58 mm yr-1 and 765 ± 112 vs. 748 ± 124 gC m-2 yr-1 for ET and GPP, respectively). Comparison with MODIS products showed consistently lower estimates from the MODIS-based models, particularly at the forest sites. Using the adjusted RS-Met, we show that afforestation significantly increased the water use efficiency (the ratio of carbon uptake to ET) in this region

  9. Effect of Irrigation with Reclaimed Water on Fruit Characteristics and Photosynthesis of Olive Trees under Two Irrigation Systems

    Directory of Open Access Journals (Sweden)

    N. Ashrafi

    2016-02-01

    Full Text Available Introduction: Olive (Olea europaea L. trees are mainly cultivated in the Mediterranean area and are grown for their oil or processed as table olives. Despite the fact that olive is known to be resistant to drought conditions due to its anatomical, physiological, and biochemical adaptations to drought stress, reports indicate that the olive can be adversely affected by drought stress, which has a negative effect on the growth of olive trees. In the absence of adequate supplies of water, the demand for water can be met by using improved irrigation methods or by using reclaimed water (RW. Reports have shown that recycled water has been used successfully for irrigating olive orchards with no negative effects on plant growth.Attention has been paid to reclaimed water as one of the most significant available water resources used in agriculture around large cities in arid and semi-arid regions. On the other hand, irrigation efficiency is low and does not meet the demands of farmers.In order to investigate the possibility of irrigating olive orchards with subsurface leakage irrigation (SLI in application of reclaimed water, an experiment was carried out with the aim of investigating the effect of reclaimed water on photosynthetic indices and morphological properties of olive fruit. Materials and Methods: Research was conducted using a split-plot experimental design with two factors (irrigation system and water quality on the campus of Isfahan University of Technology in Isfahan, Iran, on a sandy-clay soil with a pH of 7.5 and electrical conductivity (EC of 2.48 dSm-1.PVC leaky tubes were used for the SLI system. The SLI system was installed 40 cm from the crown of each tree at a depth of 30 - 40 cm.At the end of the experiment fruit yield, weight per fruit, volume, length and firmness were calculated. A portable gas exchange system (Li-6400., LICOR, Lincoln, NE, USA was used to measure the net rate photosynthesis (A, the internal partial pressure CO2

  10. Anatomical and hydraulic properties of sorghum roots exposed to water deficit. [Sorghum bicolor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, R.T.; Jordan, W.R.; Drew, M.C. (Texas A and M Univ., College Station (United States))

    1991-05-01

    The effects of a severe water stress in the upper 0-0.15 m rooting zone on development of the exodermis, endodermis and xylem and on radial (Lp) and axial (Ls) hydraulic conductances were studied for Sorghum bicolor. Lp and Lx were based on water flow rates obtained by applying a negative hydrostatic pressure to the proximal xylem ends of excised roots placed in aerated nutrient solution. The same roots were stained with fluorescent berberine and acid phloroglucinol to describe the development of the exodermal and endodermal cell walls from formation of the Casparian band (State I), to deposition of suberin lamellae (State II), and lignification (State III). Lp of 1.5 {times} 10{sup {minus}11} m{sup 3}s{sup {minus}1}MPa{sup {minus}1} was 80% lower in stressed roots than in unstressed controls. At 0.01 and 0.07 m from the root apex, stressed roots were in State III while control roots were in States I and II, respectively. SEM-image analysis for stressed roots indicated that in the exodermis a greater proportion of the cross sectional area was occupied by lignified walls than in the endodermis. Cellufluor, an apoplastic tracer, was blocked at the lignified exodermis even at 0.01 m from the apex in stressed roots. Uranin, a symplastic tracer, was taken up only in the apical region in stressed roots but farther from the apex in the controls. Lx of 7.1 {times} 10{sup {minus}11}m{sup 3}s{sup {minus}1}MPa{sup {minus}1} was 90% lower in stressed roots compared with the controls. Cellufluor test and image analysis showed that although the protoxylem and early metaxylem were conductive in both treatments, stress caused more than a 50% reduction in the diameter of the xylem elements. Results suggest that lignification of the exodermis and endodermis to a large extent decreased apoplastic and symplastic flows and hence Lp in stressed roots. The low Lx in stressed roots was due to a decrease in the diameters of the conductive xylem elements.

  11. Genome wide association study (GWAS) for grain yield in rice cultivated under water deficit.

    Science.gov (United States)

    Pantalião, Gabriel Feresin; Narciso, Marcelo; Guimarães, Cléber; Castro, Adriano; Colombari, José Manoel; Breseghello, Flavio; Rodrigues, Luana; Vianello, Rosana Pereira; Borba, Tereza Oliveira; Brondani, Claudio

    2016-12-01

    The identification of rice drought tolerant materials is crucial for the development of best performing cultivars for the upland cultivation system. This study aimed to identify markers and candidate genes associated with drought tolerance by Genome Wide Association Study analysis, in order to develop tools for use in rice breeding programs. This analysis was made with 175 upland rice accessions (Oryza sativa), evaluated in experiments with and without water restriction, and 150,325 SNPs. Thirteen SNP markers associated with yield under drought conditions were identified. Through stepwise regression analysis, eight SNP markers were selected and validated in silico, and when tested by PCR, two out of the eight SNP markers were able to identify a group of rice genotypes with higher productivity under drought. These results are encouraging for deriving markers for the routine analysis of marker assisted selection. From the drought experiment, including the genes inherited in linkage blocks, 50 genes were identified, from which 30 were annotated, and 10 were previously related to drought and/or abiotic stress tolerance, such as the transcription factors WRKY and Apetala2, and protein kinases.

  12. Genome-wide analysis of WRKY transcription factors in wheat (Triticum aestivum L.) and differential expression under water deficit condition.

    Science.gov (United States)

    Ning, Pan; Liu, Congcong; Kang, Jingquan; Lv, Jinyin

    2017-01-01

    WRKY proteins, which comprise one of the largest transcription factor (TF) families in the plant kingdom, play crucial roles in plant development and stress responses. Despite several studies on WRKYs in wheat (Triticum aestivum L.), functional annotation information about wheat WRKYs is limited. Here, 171 TaWRKY TFs were identified from the whole wheat genome and compared with proteins from 19 other species representing nine major plant lineages. A phylogenetic analysis, coupled with gene structure analysis and motif determination, divided these TaWRKYs into seven subgroups (Group I, IIa-e, and III). Chromosomal location showed that most TaWRKY genes were enriched on four chromosomes, especially on chromosome 3B. In addition, 85 (49.7%) genes were either tandem (5) or segmental duplication (80), which suggested that though tandem duplication has contributed to the expansion of TaWRKY family, segmental duplication probably played a more pivotal role. Analysis of cis-acting elements revealed putative functions of WRKYs in wheat during development as well as under numerous biotic and abiotic stresses. Finally, the expression of TaWRKY genes in flag leaves, glumes, and lemmas under water-deficit condition were analyzed. Results showed that different TaWRKY genes preferentially express in specific tissue during the grain-filling stage. Our results provide a more extensive insight on WRKY gene family in wheat, and also contribute to the screening of more candidate genes for further investigation on function characterization of WRKYs under various stresses.

  13. Genome-Wide Identification of MicroRNAs in Leaves and the Developing Head of Four Durum Genotypes during Water Deficit Stress.

    Directory of Open Access Journals (Sweden)

    Haipei Liu

    Full Text Available MicroRNAs (miRNAs are small non-coding RNAs that play critical roles in plant development and abiotic stress responses. The miRNA transcriptome (miRNAome under water deficit stress has been investigated in many plant species, but is poorly characterised in durum wheat (Triticum turgidum L. ssp. durum. Water stress during early reproductive stages can result in significant yield loss in durum wheat and this study describes genotypic differences in the miRNAome between water deficit tolerant and sensitive durum genotypes. Small RNA libraries (96 in total were constructed from flag leaf and developing head tissues of four durum genotypes, with or without water stress to identify differentially abundant miRNAs. Illumina sequencing detected 110 conserved miRNAs and 159 novel candidate miRNA hairpins with 66 conserved miRNAs and five novel miRNA hairpins differentially abundant under water deficit stress. Ten miRNAs (seven conserved, three novel were validated through qPCR. Several conserved and novel miRNAs showed unambiguous inverted regulatory profiles between the durum genotypes. Several miRNAs also showed differential abundance between two tissue types regardless of treatment. Predicted mRNA targets (130 of four novel durum miRNAs were characterised using Gene Ontology (GO which revealed functions common to stress responses and plant development. Negative correlation was observed between several target genes and the corresponding miRNA under water stress. For the first time, we present a comprehensive study of the durum miRNAome under water deficit stress. The identification of differentially abundant miRNAs provides molecular evidence that miRNAs are potential determinants of water stress tolerance in durum wheat. GO analysis of predicted targets contributes to the understanding of genotypic physiological responses leading to stress tolerance capacity. Further functional analysis of specific stress responsive miRNAs and their interaction with

  14. Selenium (Se) seed priming induced growth and biochemical changes in wheat under water deficit conditions.

    Science.gov (United States)

    Nawaz, Fahim; Ashraf, M Yasin; Ahmad, Rashid; Waraich, Ejaz Ahmad

    2013-02-01

    Insufficient stand establishment at early growth stages in wheat (Triticum aestivum L.) due to drought stress is a major problem that limits overall efficiency and yield of crop. Priming of seed is an effective method for raising seed performance and improving tolerance of crops to abiotic stresses especially drought. The seeds of two local wheat cultivars (Kohistan-97 and Pasban-90) were soaked in distilled water or sodium selenate solutions of 25, 50, 75, and 100 μM for 1/2 or 1 h at 25 °C and later re-dried to their original moisture levels before sowing. One-hour priming significantly increased root length stress tolerance index, dry matter stress tolerance index, and total biomass of seedlings; however, no significant effect of changing duration of Se seed priming was observed on plant height stress tolerance index and shoot/root ratio. Among cultivars, Kohistan-97 was found to be more responsive to Se seed treatment as 1 h priming at 100 μM significantly increased its total biomass by 43 % as compared to control treatment. Although biomass of seedlings was not affected with Se seed priming under normal conditions, but it increased significantly with increase in rates of Se under drought stress conditions. One-hour priming at 75 μM increased the total sugar content and total free amino acids in both wheat cultivars. A more significant decrease in soluble proteins of seedlings was observed by 1 h priming than 1/2 h priming under drought stress conditions.

  15. Water deficit stress mitigation by calcium chloride in Catharanthus roseus: effects on oxidative stress, proline metabolism and indole alkaloid accumulation.

    Science.gov (United States)

    Jaleel, C Abdul; Manivannan, P; Sankar, B; Kishorekumar, A; Gopi, R; Somasundaram, R; Panneerselvam, R

    2007-10-15

    The present investigation was conducted to determine whether CaCl(2) increases Catharanthus roseus drought tolerance and if such tolerance is correlated with changes in oxidative stress, osmoregulation and indole alkaloid accumulation. C. roseus plants were grown under water deficit environments with or without CaCl(2). Drought induced oxidative stress was measured in terms of lipid peroxidation (LPO) and H(2)O(2) contents, osmolyte concentration, proline (PRO) metabolizing enzymes and indole alkaloid accumulation. The plants under pot culture were subjected to 10, 15 and 20 days interval drought (DID) stress and drought stress with 5mM CaCl(2) and 5mM CaCl(2) alone from 30 days after planting (DAP) and regular irrigation was kept as control. The plants were uprooted on 41 DAS (10 DID), 46 DAS (15 DID) and 51 DAS (20 DID). Drought stressed plants showed increased LPO, H(2)O(2), glycine betaine (GB) and PRO contents and decreased proline oxidase (PROX) activity and increased gamma-glutamyl kinase (gamma-GK) activity when compared to control. Addition of CaCl(2) to drought stressed plants lowered the PRO concentration by increasing the level of PROX and decreasing the gamma-GK activities. Calcium ions increased the GB contents. CaCl(2) appears to confer greater osmoprotection by the additive role with drought in GB accumulation. The drought with CaCl(2)-treated C. roseus plants showed an increase in total indole alkaloid content in shoots and roots when compared to drought stressed and well-watered plants.

  16. Shoot water relations of mature black spruce families displaying a genotype × environment interaction in growth rate. III. Diurnal patterns as influenced by vapor pressure deficit and internal water status

    Science.gov (United States)

    John E. Major; Kurt H. Johnsen

    2001-01-01

    Pressure­volume curves were constructed and shoot water potentials measured for +20-year-old black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families growing on a moist site and a dry site at the Petawawa Research Forest, Ontario, to determine whether differences in diurnal water relations traits were related to productivity. To...

  17. A Soil-Plate Based Pipeline for Assessing Cereal Root Growth in Response to Polyethylene Glycol (PEG-Induced Water Deficit Stress

    Directory of Open Access Journals (Sweden)

    Sven K. Nelson

    2017-07-01

    Full Text Available Drought is a serious problem that causes losses in crop-yield every year, but the mechanisms underlying how roots respond to water deficit are difficult to study under controlled conditions. Methods for assaying root elongation and architecture, especially for seedlings, are commonly achieved on artificial media, such as agar, moistened filter paper, or in hydroponic systems. However, it has been demonstrated that measuring root characteristics under such conditions does not accurately mimic what is observed when plants are grown in soil. Morphological changes in root behavior occur because of differences in solute diffusion, mechanical impedance, exposure to light (in some designs, and gas exchange of roots grown under these conditions. To address such deficiencies, we developed a quantitative method for assaying seedling root lengths and germination in soil using a plate-based approach with wheat as a model crop. We also further developed the method to include defined water deficits stress levels using the osmotic properties of polyethylene glycol (PEG. Seeds were sown into soil-filled vertical plates and grown in the dark. Root length measurements were collected using digital photography through the transparent lid under green lighting to avoid effects of white light exposure on growth. Photographs were analyzed using the cross-platform ImageJ plugin, SmartRoot, which can detect root edges and partially automate root detection for extraction of lengths. This allowed for quick measurements and straightforward and accurate assessments of non-linear roots. Other measurements, such as root width or angle, can also be collected by this method. An R function was developed to collect exported root length data, process and reformat the data, and output plots depicting root/shoot growth dynamics. For water deficit experiments, seedlings were transplanted side-by-side into well-watered plates and plates containing PEG solutions to simulate precise

  18. The Development of Intensive Care Unit Acquired Hypernatremia Is Not Explained by Sodium Overload or Water Deficit: A Retrospective Cohort Study on Water Balance and Sodium Handling.

    Science.gov (United States)

    van IJzendoorn, M C O; Buter, H; Kingma, W P; Navis, G J; Boerma, E C

    2016-01-01

    Background. ICU acquired hypernatremia (IAH, serum sodium concentration (sNa) ≥ 143 mmol/L) is mainly considered iatrogenic, induced by sodium overload and water deficit. Main goal of the current paper was to answer the following questions: Can the development of IAH indeed be explained by sodium intake and water balance? Or can it be explained by renal cation excretion? Methods. Two retrospective studies were conducted: a balance study in 97 ICU patients with and without IAH and a survey on renal cation excretion in 115 patients with IAH. Results. Sodium intake within the first 48 hours of ICU admission was 12.5 [9.3-17.5] g in patients without IAH (n = 50) and 15.8 [9-21.9] g in patients with IAH (n = 47), p = 0.13. Fluid balance was 2.3 [1-3.7] L and 2.5 [0.8-4.2] L, respectively, p = 0.77. Urine cation excretion (urine Na + K) was cation excretion, respectively. Conclusion. IAH is not explained by sodium intake or fluid balance. Patients with IAH are characterized by low urine cation excretion, despite positive fluid balances. The current paradigm does not seem to explain IAH to the full extent and warrants further studies on sodium handling in ICU patients.

  19. Removal of nutrient limitations by long-term fertilization decreases nocturnal water loss in savanna trees.

    Science.gov